Fix spelling mistake

Closes #2029

include/git2/types.h

@@ -131,7 +131,7 @@ typedef struct git_treebuilder git_treebuilder;
 /** Memory representation of an index file. */
 typedef struct git_index git_index;
 
-/** An interator for conflicts in the index. */
+/** An iterator for conflicts in the index. */
 typedef struct git_index_conflict_iterator git_index_conflict_iterator;
 
 /** Memory representation of a set of config files */