fix: [vps] provide better help support for stats, listing available resources

bin/vps

@@ -2168,13 +2168,17 @@ awk:require() {
     done
 }
 
+resource:list() {
+    declare -F | egrep -- '-fx? stats:[a-zA-Z0-9_.-]+$' | cut -f 3- -d " " | cut -f 2- -d ":"
+}
 
 cmdline.spec.gnu stats
 cmdline.spec::cmd:stats:run() {
 
     : :optval: --format,-f    "Either 'silent', 'raw', or 'pretty', default is pretty."
     : :optfla: --silent,-s    "Shorthand for '--format silent'"
-    : :optval: --resource,-r   'resource(s) separated with a comma'
+    : :optval: --resource,-r   "resource(s) separated with a comma
+                                (available resources: $(resource:list))"
 
 
     local project_name service_name containers container check
@@ -2222,7 +2226,7 @@ cmdline.spec::cmd:stats:run() {
         not_found_msg=${not_found_msg%, }
         err "Unsupported resource(s) provided: ${not_found_msg}"
         echo "  resource must be one-of:" >&2
-        declare -F | egrep -- '-fx? stats:[a-zA-Z0-9_.-]+$' | cut -f 3- -d " " | cut -f 2- -d ":" | prefix "  - " >&2
+        resource:list | prefix "  - " >&2
         return 1
     fi