update Discord and GHC info

index.md

@@ -9,8 +9,7 @@ Swarm is a terminal-based 2D programming and resource gathering
 game. Program your robots to explore the world and collect resources,
 which in turn allows you to build upgraded robots that can run more
 interesting and complex programs.  Check out the [installation
-instructions](/installing), join the [IRC
-channel](https://github.com/swarm-game/swarm/blob/main/COMMUNITY.md),
+instructions](/installing), join the [Discord server](https://github.com/swarm-game/swarm/blob/main/COMMUNITY.md),
 take a look at the [wiki](https://github.com/swarm-game/swarm/wiki),
 or [see how you can
 contribute](https://github.com/swarm-game/swarm/blob/main/CONTRIBUTING.md)!

installing.md

@@ -49,9 +49,7 @@ able to install with
 
     cabal install swarm
 
-Currently Swarm supports GHC 9.2, 9.4, or 9.6 (GHC 9.8 support should
-be coming soon; it's possible that it already supports 9.8 but we
-forgot to update this message).
+Currently Swarm builds with GHC 9.2 through 9.8.
 
 If you don't already have the `cabal` tool, first [install
 `ghcup`](https://www.haskell.org/ghcup/), then run `ghcup install