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/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.
*/