CLEANUP: assorted typo fixes in the code and comments

This is 7th iteration of typo fixes
diff --git a/ebtree/ebistree.h b/ebtree/ebistree.h
index 0c99548..a438fa1 100644
--- a/ebtree/ebistree.h
+++ b/ebtree/ebistree.h
@@ -39,7 +39,7 @@
 struct ebpt_node *ebis_insert(struct eb_root *root, struct ebpt_node *new);
 
 /* 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
+ * It's the caller's responsibility 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.
  */
@@ -55,7 +55,7 @@
 }
 
 /* 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
+ * It's the caller's responsibility to use this function only on trees which
  * only contain zero-terminated strings. If none can be found, return NULL.
  */
 static forceinline struct ebpt_node *__ebis_lookup(struct eb_root *root, const void *x)