Move bash completion logic to new subcommand: pull

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

contrib/completion/bash/docker

@@ -2148,7 +2148,25 @@ _docker_image_prune() {
 }
 
 _docker_image_pull() {
-	_docker_pull
+	case "$cur" in
+		-*)
+			COMPREPLY=( $( compgen -W "--all-tags -a --disable-content-trust=false --help" -- "$cur" ) )
+			;;
+		*)
+			local counter=$(__docker_pos_first_nonflag)
+			if [ $cword -eq $counter ]; then
+				for arg in "${COMP_WORDS[@]}"; do
+					case "$arg" in
+						--all-tags|-a)
+							__docker_complete_image_repos
+							return
+							;;
+					esac
+				done
+				__docker_complete_image_repos_and_tags
+			fi
+			;;
+	esac
 }
 
 _docker_image_push() {
@@ -3005,25 +3023,7 @@ _docker_ps() {
 }
 
 _docker_pull() {
-	case "$cur" in
-		-*)
-			COMPREPLY=( $( compgen -W "--all-tags -a --disable-content-trust=false --help" -- "$cur" ) )
-			;;
-		*)
-			local counter=$(__docker_pos_first_nonflag)
-			if [ $cword -eq $counter ]; then
-				for arg in "${COMP_WORDS[@]}"; do
-					case "$arg" in
-						--all-tags|-a)
-							__docker_complete_image_repos
-							return
-							;;
-					esac
-				done
-				__docker_complete_image_repos_and_tags
-			fi
-			;;
-	esac
+	_docker_image_pull
 }
 
 _docker_push() {