btrfs-progs: doc: fix short explanation of restore in btrfs

Short explanation of restore is wrong. Fix it.

Signed-off-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Author: Tsutomu Itoh

Documentation/btrfs.asciidoc

@@ -75,7 +75,7 @@ COMMANDS
 	See `btrfs-rescue`(8) for details.
 
 *restore*::
-	Manage a btrfs filesystem, including label setting/sync and so on. +
+	Try to restore files from a damaged btrfs filesystem. +
 	See `btrfs-restore`(8) for details.
 
 *scrub*::