grim: Limit meta.platforms to linux

meta.platforms was changed in PR #342840, which causes darwin build failures.

Also update meta.homepage.

ZHF: #352882

pkgs/by-name/gr/grim/package.nix

@@ -46,11 +46,11 @@ stdenv.mkDerivation (finalAttrs: {
   strictDeps = true;
 
   meta = {
-    homepage = "https://github.com/emersion/grim";
+    homepage = "https://sr.ht/~emersion/grim";
     description = "Grab images from a Wayland compositor";
     license = lib.licenses.mit;
     mainProgram = "grim";
     maintainers = with lib.maintainers; [ AndersonTorres ];
-    inherit (wayland.meta) platforms;
+    platforms = lib.platforms.linux;
   };
 })