chore: add more development dependencies to packages.nix + some notes

nix/packages.nix

@@ -8,12 +8,22 @@
 # (see the output value of CRYSTAL_LIBRARY_PATH when running `crystal env`
 # Ref: https://github.com/NixOS/nixpkgs/blob/nixos-26.05/pkgs/development/compilers/crystal/default.nix#L231)
 #
+# This dependencies have been tested and used for development with the Zed
+# editor, and the Crystal extension https://github.com/crystal-lang-tools/zed-crystal.
+# They should work just fine on any other editor that supports `direnv`
+#
+# (VSCode supports `direnv` with Nix Flakes with this extension:
+# https://github.com/direnv/direnv-vscode)
 with pkgs;
 [
   # Invidious dependencies
   crystal_1_19
   sqlite
   shards
+  crystalline # LSP, is not that good, but still useful.
+  pkg-config # Required by crystalline
+  ameba # For linting
+  ameba-ls # LSP for the ameba linter, to get inline messages from ameba
   # Utilities
   nixd # Nixd LSP to format .nix files
 ]