Fix usage for `docker volume inspect` and `docker volume rm`

For both commands, volume is _not_ optional. Several volumes may
be specified.
Both commands now use the same name (VOLUME) for the command argument.

Signed-off-by: Harald Albers <github@albersweb.de>

docs/reference/commandline/volume_inspect.md

@@ -10,9 +10,9 @@ parent = "smn_cli"
 
 # volume inspect
 
-    Usage: docker volume inspect [OPTIONS] [VOLUME NAME]
+    Usage: docker volume inspect [OPTIONS] VOLUME [VOLUME...]
 
-    Inspect a volume
+    Inspect one or more volumes
 
     -f, --format=       Format the output using the given go template.
 

docs/reference/commandline/volume_rm.md

@@ -10,13 +10,13 @@ parent = "smn_cli"
 
 # volume rm
 
-    Usage: docker volume rm [OPTIONS] [VOLUME NAME]
+    Usage: docker volume rm [OPTIONS] VOLUME [VOLUME...]
 
     Remove a volume
 
     --help=false       Print usage
 
-Removes a volume. You cannot remove a volume that is in use by a container.
+Removes one or more volumes. You cannot remove a volume that is in use by a container.
 
   $ docker volume rm hello
   hello

man/docker-volume-inspect.1.md

@@ -8,11 +8,11 @@ docker-volume-inspect - Get low-level information about a volume
 **docker volume inspect**
 [**-f**|**--format**[=**]]
 
-[OPTIONS] [VOLUME NAME]
+[OPTIONS] VOLUME [VOLUME...]
 
 # DESCRIPTION
 
-Returns information about a volume. By default, this command renders all results
+Returns information about one or more volumes. By default, this command renders all results
 in a JSON array. You can specify an alternate format to execute a given template
 is executed for each result. Go's
 http://golang.org/pkg/text/template/ package describes all the details of the

man/docker-volume-rm.1.md

@@ -7,11 +7,11 @@ docker-volume-rm - Remove a volume
 # SYNOPSIS
 **docker volume rm**
 
-[OPTIONS] [VOLUME NAME]
+[OPTIONS] VOLUME [VOLUME...]
 
 # DESCRIPTION
 
-Removes a volume. You cannot remove a volume that is in use by a container.
+Removes one or more volumes. You cannot remove a volume that is in use by a container.
 
     ```
     $ docker volume rm hello