struct ref_entry: document name member

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

refs.c

@@ -12,6 +12,7 @@ struct ref_entry {
 	unsigned char flag; /* ISSYMREF? ISPACKED? */
 	unsigned char sha1[20];
 	unsigned char peeled[20];
+	/* The full name of the reference (e.g., "refs/heads/master"): */
 	char name[FLEX_ARRAY];
 };