CLEANUP: fix typos in comments in ebtree

This is mainly about misspells of the word "occurrence". The misspells
are only located in code comments.
diff --git a/ebtree/eb32tree.h b/ebtree/eb32tree.h
index f33eb86..08ff900 100644
--- a/ebtree/eb32tree.h
+++ b/ebtree/eb32tree.h
@@ -129,7 +129,7 @@
 }
 
 /*
- * Find the first occurence of a key in the tree <root>. If none can be
+ * Find the first occurrence of a key in the tree <root>. If none can be
  * found, return NULL.
  */
 static forceinline struct eb32_node *__eb32_lookup(struct eb_root *root, u32 x)
@@ -180,7 +180,7 @@
 }
 
 /*
- * Find the first occurence of a signed key in the tree <root>. If none can
+ * Find the first occurrence of a signed key in the tree <root>. If none can
  * be found, return NULL.
  */
 static forceinline struct eb32_node *__eb32i_lookup(struct eb_root *root, s32 x)
diff --git a/ebtree/eb64tree.h b/ebtree/eb64tree.h
index 2ab833f..6d0d039 100644
--- a/ebtree/eb64tree.h
+++ b/ebtree/eb64tree.h
@@ -129,7 +129,7 @@
 }
 
 /*
- * Find the first occurence of a key in the tree <root>. If none can be
+ * Find the first occurrence of a key in the tree <root>. If none can be
  * found, return NULL.
  */
 static forceinline struct eb64_node *__eb64_lookup(struct eb_root *root, u64 x)
@@ -178,7 +178,7 @@
 }
 
 /*
- * Find the first occurence of a signed key in the tree <root>. If none can
+ * Find the first occurrence of a signed key in the tree <root>. If none can
  * be found, return NULL.
  */
 static forceinline struct eb64_node *__eb64i_lookup(struct eb_root *root, s64 x)
diff --git a/ebtree/ebimtree.c b/ebtree/ebimtree.c
index 092a0ac..8a75cd8 100644
--- a/ebtree/ebimtree.c
+++ b/ebtree/ebimtree.c
@@ -23,7 +23,7 @@
 #include "ebpttree.h"
 #include "ebimtree.h"
 
-/* Find the first occurence of a key of <len> bytes in the tree <root>.
+/* Find the first occurrence of a key of <len> bytes in the tree <root>.
  * If none can be found, return NULL.
  */
 REGPRM3 struct ebpt_node *
diff --git a/ebtree/ebimtree.h b/ebtree/ebimtree.h
index 99e7503..4a98c96 100644
--- a/ebtree/ebimtree.h
+++ b/ebtree/ebimtree.h
@@ -35,7 +35,7 @@
 REGPRM3 struct ebpt_node *ebim_lookup(struct eb_root *root, const void *x, unsigned int len);
 REGPRM3 struct ebpt_node *ebim_insert(struct eb_root *root, struct ebpt_node *new, unsigned int len);
 
-/* Find the first occurence of a key of a least <len> bytes matching <x> in the
+/* Find the first occurrence of a key of a least <len> bytes matching <x> in the
  * tree <root>. The caller is responsible for ensuring that <len> will not exceed
  * the common parts between the tree's keys and <x>. In case of multiple matches,
  * the leftmost node is returned. This means that this function can be used to
@@ -89,7 +89,7 @@
 		 */
 		node_bit = ~node_bit + (pos << 3) + 8; // = (pos<<3) + (7 - node_bit)
 		if (node_bit < 0) {
-			/* This surprizing construction gives better performance
+			/* This surprising construction gives better performance
 			 * because gcc does not try to reorder the loop. Tested to
 			 * be fine with 2.95 to 4.2.
 			 */
diff --git a/ebtree/ebistree.c b/ebtree/ebistree.c
index 222a437..d3dc0c5 100644
--- a/ebtree/ebistree.c
+++ b/ebtree/ebistree.c
@@ -22,7 +22,7 @@
 
 #include "ebistree.h"
 
-/* Find the first occurence of a zero-terminated string <x> in the tree <root>.
+/* Find the first occurrence of a zero-terminated string <x> in the tree <root>.
  * It's the caller's reponsibility to use this function only on trees which
  * only contain zero-terminated strings. If none can be found, return NULL.
  */
diff --git a/ebtree/ebistree.h b/ebtree/ebistree.h
index e1bcbc7..9c4fd8c 100644
--- a/ebtree/ebistree.h
+++ b/ebtree/ebistree.h
@@ -38,7 +38,7 @@
 REGPRM2 struct ebpt_node *ebis_lookup(struct eb_root *root, const char *x);
 REGPRM2 struct ebpt_node *ebis_insert(struct eb_root *root, struct ebpt_node *new);
 
-/* Find the first occurence of a length <len> string <x> in the tree <root>.
+/* Find the first occurrence of a length <len> string <x> in the tree <root>.
  * It's the caller's reponsibility to use this function only on trees which
  * only contain zero-terminated strings, and that no null character is present
  * in string <x> in the first <len> chars. If none can be found, return NULL.
@@ -54,7 +54,7 @@
 	return node;
 }
 
-/* Find the first occurence of a zero-terminated string <x> in the tree <root>.
+/* Find the first occurrence of a zero-terminated string <x> in the tree <root>.
  * It's the caller's reponsibility to use this function only on trees which
  * only contain zero-terminated strings. If none can be found, return NULL.
  */
diff --git a/ebtree/ebmbtree.c b/ebtree/ebmbtree.c
index ebd6b8b..5fbef20 100644
--- a/ebtree/ebmbtree.c
+++ b/ebtree/ebmbtree.c
@@ -22,7 +22,7 @@
 
 #include "ebmbtree.h"
 
-/* Find the first occurence of a key of <len> bytes in the tree <root>.
+/* Find the first occurrence of a key of <len> bytes in the tree <root>.
  * If none can be found, return NULL.
  */
 REGPRM3 struct ebmb_node *
@@ -42,7 +42,7 @@
 	return __ebmb_insert(root, new, len);
 }
 
-/* Find the first occurence of the longest prefix matching a key <x> in the
+/* Find the first occurrence of the longest prefix matching a key <x> in the
  * tree <root>. It's the caller's responsibility to ensure that key <x> is at
  * least as long as the keys in the tree. If none can be found, return NULL.
  */
@@ -52,7 +52,7 @@
 	return __ebmb_lookup_longest(root, x);
 }
 
-/* Find the first occurence of a prefix matching a key <x> of <pfx> BITS in the
+/* Find the first occurrence of a prefix matching a key <x> of <pfx> BITS in the
  * tree <root>. If none can be found, return NULL.
  */
 REGPRM3 struct ebmb_node *
diff --git a/ebtree/ebmbtree.h b/ebtree/ebmbtree.h
index 5ab115d..6ed7de4 100644
--- a/ebtree/ebmbtree.h
+++ b/ebtree/ebmbtree.h
@@ -123,7 +123,7 @@
 	__eb_delete(&ebmb->node);
 }
 
-/* Find the first occurence of a key of a least <len> bytes matching <x> in the
+/* Find the first occurrence of a key of a least <len> bytes matching <x> in the
  * tree <root>. The caller is responsible for ensuring that <len> will not exceed
  * the common parts between the tree's keys and <x>. In case of multiple matches,
  * the leftmost node is returned. This means that this function can be used to
@@ -176,7 +176,7 @@
 		 */
 		node_bit = ~node_bit + (pos << 3) + 8; // = (pos<<3) + (7 - node_bit)
 		if (node_bit < 0) {
-			/* This surprizing construction gives better performance
+			/* This surprising construction gives better performance
 			 * because gcc does not try to reorder the loop. Tested to
 			 * be fine with 2.95 to 4.2.
 			 */
@@ -371,7 +371,7 @@
 }
 
 
-/* Find the first occurence of the longest prefix matching a key <x> in the
+/* Find the first occurrence of the longest prefix matching a key <x> in the
  * tree <root>. It's the caller's responsibility to ensure that key <x> is at
  * least as long as the keys in the tree. Note that this can be ensured by
  * having a byte at the end of <x> which cannot be part of any prefix, typically
@@ -465,7 +465,7 @@
 }
 
 
-/* Find the first occurence of a prefix matching a key <x> of <pfx> BITS in the
+/* Find the first occurrence of a prefix matching a key <x> of <pfx> BITS in the
  * tree <root>. It's the caller's responsibility to ensure that key <x> is at
  * least as long as the keys in the tree. Note that this can be ensured by
  * having a byte at the end of <x> which cannot be part of any prefix, typically
diff --git a/ebtree/ebsttree.c b/ebtree/ebsttree.c
index cfd3266..88b8139 100644
--- a/ebtree/ebsttree.c
+++ b/ebtree/ebsttree.c
@@ -22,7 +22,7 @@
 
 #include "ebsttree.h"
 
-/* Find the first occurence of a zero-terminated string <x> in the tree <root>.
+/* Find the first occurrence of a zero-terminated string <x> in the tree <root>.
  * It's the caller's reponsibility to use this function only on trees which
  * only contain zero-terminated strings. If none can be found, return NULL.
  */
diff --git a/ebtree/ebsttree.h b/ebtree/ebsttree.h
index f86101d..cd6994c 100644
--- a/ebtree/ebsttree.h
+++ b/ebtree/ebsttree.h
@@ -32,7 +32,7 @@
 REGPRM2 struct ebmb_node *ebst_lookup(struct eb_root *root, const char *x);
 REGPRM2 struct ebmb_node *ebst_insert(struct eb_root *root, struct ebmb_node *new);
 
-/* Find the first occurence of a length <len> string <x> in the tree <root>.
+/* Find the first occurrence of a length <len> string <x> in the tree <root>.
  * It's the caller's reponsibility to use this function only on trees which
  * only contain zero-terminated strings, and that no null character is present
  * in string <x> in the first <len> chars. If none can be found, return NULL.
@@ -48,7 +48,7 @@
 	return node;
 }
 
-/* Find the first occurence of a zero-terminated string <x> in the tree <root>.
+/* Find the first occurrence of a zero-terminated string <x> in the tree <root>.
  * It's the caller's reponsibility to use this function only on trees which
  * only contain zero-terminated strings. If none can be found, return NULL.
  */