Add a few translator comments for frontend strings

Consistently rename "team chat" to "clan chat" (except chat command) Only change in strings, no functional change. "Team" and "clan" have defined meanings in HW, but "team chat" oddly broke this convention. This feature allows chat with your clan, not with your team, so is now called "clan chat". /team command unchanged to avoid disruption (for now).

Make engine chat syntax translatable The message syntax you see when someone uses chat, e.g. - Player 1: message - [Team]: message - [hedgehog name]: message