Fix misspelling of git_index_append2 (was git_index_apppend2).

include/git2/index.h

@@ -232,7 +232,7 @@ GIT_EXTERN(int) git_index_append(git_index *index, const char *path, int stage);
  * @param source_entry new entry object
  * @return 0 on success, otherwise an error code
  */
-GIT_EXTERN(int) git_index_apppend2(git_index *index, const git_index_entry *source_entry);
+GIT_EXTERN(int) git_index_append2(git_index *index, const git_index_entry *source_entry);
 
 /**
  * Remove an entry from the index

src/index.c

@@ -421,7 +421,7 @@ int git_index_add2(git_index *index, const git_index_entry *source_entry)
 	return index_insert(index, source_entry, 1);
 }
 
-int git_index_apppend2(git_index *index, const git_index_entry *source_entry)
+int git_index_append2(git_index *index, const git_index_entry *source_entry)
 {
 	return index_insert(index, source_entry, 0);
 }