Update man pages to refect the latest cli change

The major change is the description of options, change
it as the latest cli help message shows, which specify
a "value" after an option if it takes value, and add
(default: xxx) if the option has a default value.

This also includes some other minor consistency fixes.

Signed-off-by: Qiang Huang <h.huangqiang@huawei.com>

restore.go

@@ -53,7 +53,7 @@ using the runc checkpoint command.`,
 		cli.StringFlag{
 			Name:  "manage-cgroups-mode",
 			Value: "",
-			Usage: "cgroups mode: 'soft' (default), 'full' and 'strict'.",
+			Usage: "cgroups mode: 'soft' (default), 'full' and 'strict'",
 		},
 		cli.StringFlag{
 			Name:  "bundle, b",