git-reflog: document --verbose

Signed-off-by: Michele Ballabio <barra_cuda@katamail.com>
Signed-off-by: Lars Hjemli <hjemli@gmail.com>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

Documentation/git-reflog.txt

@@ -16,7 +16,7 @@ The command takes various subcommands, and different options
 depending on the subcommand:
 
 [verse]
-git reflog expire [--dry-run] [--stale-fix]
+git reflog expire [--dry-run] [--stale-fix] [--verbose]
 	[--expire=<time>] [--expire-unreachable=<time>] [--all] <refs>...
 
 git reflog [show] [log-options]
@@ -68,6 +68,9 @@ them.
 --all::
 	Instead of listing <refs> explicitly, prune all refs.
 
+--verbose::
+	Print extra information on screen.
+
 Author
 ------
 Written by Junio C Hamano <junkio@cox.net>