fix feature_advanced_keycodes.md's link (#7421)

docs/feature_advanced_keycodes.md has:
```
[Tap Dance](https://github.com/qmk/qmk_firmware/blob/master/docs/feature_tap_dance.md#example-5-using-tap-dance-for-advanced-mod-tap-and-layer-tap-keys)
```

change to:
```
[Tap Dance](feature_tap_dance.md#example-5-using-tap-dance-for-advanced-mod-tap-and-layer-tap-keys)
```

docs/feature_advanced_keycodes.md

@@ -15,7 +15,7 @@ This will allow you to use `FN_CAPS` and `ALT_TAB` in your keymap, keeping it mo
 
 ## Caveats
 
-Currently, `LT()` and `MT()` are limited to the [Basic Keycode set](keycodes_basic.md), meaning you can't use keycodes like `LCTL()`, `KC_TILD`, or anything greater than `0xFF`. Modifiers specified as part of a Layer Tap or Mod Tap's keycode will be ignored. If you need to apply modifiers to your tapped keycode, [Tap Dance](https://github.com/qmk/qmk_firmware/blob/master/docs/feature_tap_dance.md#example-5-using-tap-dance-for-advanced-mod-tap-and-layer-tap-keys) can be used to accomplish this.
+Currently, `LT()` and `MT()` are limited to the [Basic Keycode set](keycodes_basic.md), meaning you can't use keycodes like `LCTL()`, `KC_TILD`, or anything greater than `0xFF`. Modifiers specified as part of a Layer Tap or Mod Tap's keycode will be ignored. If you need to apply modifiers to your tapped keycode, [Tap Dance](feature_tap_dance.md#example-5-using-tap-dance-for-advanced-mod-tap-and-layer-tap-keys) can be used to accomplish this.
 
 Additionally, if at least one right-handed modifier is specified in a Mod Tap or Layer Tap, it will cause all modifiers specified to become right-handed, so it is not possible to mix and match the two.