Fix broken color code example

main.go

@@ -91,7 +91,7 @@ func main() {
 		Long: "Colorize FILE(s), or standard input, to standard output.",
 		Example: `$ ccat FILE1 FILE2 ...
   $ ccat --bg=dark FILE1 FILE2 ... # dark background
-  $ ccat --color-code String="_darkblue_" --color-code Plaintext="darkred" FILE # set color codes
+  $ ccat -G String="_darkblue_" -G Plaintext="darkred" FILE # set color codes
   $ ccat --palette # show palette
   $ ccat # read from standard input
   $ curl https://raw.githubusercontent.com/jingweno/ccat/master/main.go | ccat`,
@@ -106,7 +106,7 @@ Flags:
 {{.LocalFlags.FlagUsages}}
 Using color is auto both by default and with --color=auto. With --color=auto,
 ccat emits color codes only when standard output is connected to a terminal.
-Color codes can be changed with --color-code KEY=VALUE. List of color codes can
+Color codes can be changed with -G KEY=VALUE. List of color codes can
 be found with --palette.
 
 Examples: