Mud Client substitutions(highlighting) for WASM

[KasparMetsa]

We now have

• MMapper WASM build. Player cannot switch mud client by design in WASM build, so the player has to use the built-in mud client. So making the built-in mud client feature-wise similar to the best mud clients is worthwhile because players have a better experience using the WASM build.
• _hotkey feature that allows to configure key bindings in WASM build.

Substitutions would be a logical next feature that any mud client would support.