neovim: fix treesitter cross compilation

hosts/common/programs/neovim/plugins.nix

@@ -186,7 +186,8 @@ with pkgs.vimPlugins;
     # docs: https://github.com/nvim-treesitter/nvim-treesitter
     # config taken from: https://github.com/i077/system/blob/master/modules/home/neovim/default.nix
     # this is required for tree-sitter to even highlight
-    plugin = nvim-treesitter.withPlugins (_: nvim-treesitter.allGrammars ++ [
+    # XXX(2024/06/03): `unison` removed because it doesn't cross compile (to armv7l-hf-multiplatform)
+    plugin = nvim-treesitter.withPlugins (_: (lib.filter (p: p.pname != "unison-grammar") nvim-treesitter.allGrammars) ++ [
       # XXX: this is apparently not enough to enable syntax highlighting!
       # nvim-treesitter ships its own queries which may be distinct from e.g. helix.
       # the queries aren't included when i ship the grammar in this manner