git reflog expire: document --stale-fix option.

Signed-off-by: Junio C Hamano <junkio@cox.net>

Documentation/git-reflog.txt

@@ -9,7 +9,7 @@ git-reflog - Manage reflog information
 SYNOPSIS
 --------
 [verse]
-'git-reflog' expire [--dry-run]
+'git-reflog' expire [--dry-run] [--stale-fix]
 	[--expire=<time>] [--expire-unreachable=<time>] [--all] <refs>...
 
 

builtin-reflog.c

@@ -13,7 +13,7 @@
  */
 
 static const char reflog_expire_usage[] =
-"git-reflog expire [--verbose] [--dry-run] [--fix-stale] [--expire=<time>] [--expire-unreachable=<time>] [--all] <refs>...";
+"git-reflog expire [--verbose] [--dry-run] [--stale-fix] [--expire=<time>] [--expire-unreachable=<time>] [--all] <refs>...";
 
 static unsigned long default_reflog_expire;
 static unsigned long default_reflog_expire_unreachable;