ref_iterator_begin_fn(): fix docstring

The iterator returned by this function only includes references whose
names start with the whole prefix, not all of those in
`find_containing_dir(prefix)` as the old docstring claimed. This
docstring was probably copy-pasted from old ref-cache code, which had
the old specification. But now, `cache_ref_iterator_begin()`
(from which the files reference iterator gets its values)
automatically wraps its output using `prefix_ref_iterator_begin()`
when necessary, so it has the stricter behavior.

Signed-off-by: Michael Haggerty <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: mhagger

refs/refs-internal.h

@@ -515,9 +515,10 @@ typedef int rename_ref_fn(struct ref_store *ref_store,
 			  const char *logmsg);
 
 /*
- * Iterate over the references in the specified ref_store that are
- * within find_containing_dir(prefix). If prefix is NULL or the empty
- * string, iterate over all references in the submodule.
+ * Iterate over the references in `ref_store` whose names start with
+ * `prefix`. `prefix` is matched as a literal string, without regard
+ * for path separators. If prefix is NULL or the empty string, iterate
+ * over all references in `ref_store`.
  */
 typedef struct ref_iterator *ref_iterator_begin_fn(
 		struct ref_store *ref_store,