fish_config theme dump: check for extra arguments

share/functions/fish_config.fish

@@ -318,6 +318,10 @@ fish_pager_color_secondary_description
 
                     return 0
                 case dump
+                    if set -q argv[1]
+                        echo "Too many arguments" >&2
+                        return 1
+                    end
                     # Write the current theme in .theme format, to stdout.
                     set -L | string match -r $theme_var_filter
                 case '*'

tests/checks/fish_config.fish

@@ -205,3 +205,6 @@ echo >$__fish_config_dir/themes/custom-from-userconf.theme \
     # CHECK: $fish_color_normal: set in universal scope, unexported, with 1 elements
     # CHECK: $fish_color_normal[1]: |normal|
 }
+
+fish_config theme dump badarg
+# CHECKERR: Too many arguments