Add completion of conf filenames to kitty @ set-colors

kitty/rc/set_colors.py

@@ -57,6 +57,7 @@ Restore all colors to the values they had at kitty startup. Note that if you spe
 this option, any color arguments are ignored and --configured and --all are implied.
 ''' + '\n\n' + MATCH_WINDOW_OPTION + '\n\n' + MATCH_TAB_OPTION.replace('--match -m', '--match-tab -t')
     argspec = 'COLOR_OR_FILE ...'
+    args_completion = {'files': ('CONF files', ('*.conf',))}
 
     def message_to_kitty(self, global_opts: RCOptions, opts: 'CLIOptions', args: ArgsType) -> PayloadType:
         final_colors: Dict[str, int] = {}