Fix plural typo in 'save' command help

The form "Save an images" is not correct.
Either "Save an image" or "Save images" work, but since
the save commands accepts multiple images, I chose the
latter.

Fixed in all places where I could grep "Save an image(s)".

Signed-off-by: Martin Mosegaard Amdisen <martin.amdisen@praqma.com>

docs/reference/commandline/save.md

@@ -12,7 +12,7 @@ parent = "smn_cli"
 
     Usage: docker save [OPTIONS] IMAGE [IMAGE...]
 
-    Save an image(s) to a tar archive (streamed to STDOUT by default)
+    Save images to a tar archive (streamed to STDOUT by default)
 
       --help             Print usage
       -o, --output=""    Write to a file, instead of STDOUT

man/docker-load.1.md

@@ -37,7 +37,7 @@ Restores both images and tags.
     fedora              latest              58394af37342        7 weeks ago         385.5 MB
 
 # See also
-**docker-save(1)** to save an image(s) to a tar archive (streamed to STDOUT by default).
+**docker-save(1)** to save images to a tar archive (streamed to STDOUT by default).
 
 # HISTORY
 April 2014, Originally compiled by William Henry (whenry at redhat dot com)

man/docker-save.1.md

@@ -2,7 +2,7 @@
 % Docker Community
 % JUNE 2014
 # NAME
-docker-save - Save an image(s) to a tar archive (streamed to STDOUT by default)
+docker-save - Save images to a tar archive (streamed to STDOUT by default)
 
 # SYNOPSIS
 **docker save**