Clarify color spec description

src/common/InputHandler.ts

@@ -2736,7 +2736,7 @@ export class InputHandler extends Disposable implements IInputHandler {
    * OSC 4; <num> ; <text> ST (set ANSI color <num> to <text>)
    *
    * @vt: #Y    OSC    4    "Set ANSI color"   "OSC 4 ; c ; spec BEL" "Change color number `c` to the color specified by `spec`."
-   * `c` is the color index between 0 and 255. `spec` color format is 'rgb:rr/gg/bb' where r, g, b are hexadecimal digits.
+   * `c` is the color index between 0 and 255. `spec` color format is 'rgb:hh/hh/hh' where `h` are hexadecimal digits.
    */
   public setAnsiColor(data: string): void {
     const event = this.parseAnsiColorChange(data);