feat(nvim): setup for ipynb dev work

Setup:
- molten (run python code)
- otter (lsp in markdown codeblocks)
- jupytext (convert .ipynb files to .md files transparently)
- image (display images inside neovim (e.g. matplotlib graphs))

flake-modules/nvim.nix

@@ -1,24 +1,22 @@
 { inputs, ... }:
-let
-  standalone = ../nvim/standalone.nix;
-in
 {
   flake.overlays.nixvim = inputs.nixvim.overlays.default;
 
   perSystem =
     { pkgs, system, ... }:
-    {
+    let
-      # Check standalone nvim build
+      nixvimLib = inputs.nixvim.lib.${system};
-      checks.nvim = inputs.nixvim.lib.${system}.check.mkTestDerivationFromNixvimModule {
+      nixvim = inputs.nixvim.legacyPackages.${system};
+      module = {
         inherit pkgs;
         module = ../nvim/standalone.nix;
       };
+    in
+    {
+      # Check standalone nvim build
+      checks.nvim = nixvimLib.check.mkTestDerivationFromNixvimModule module;
 
       # Nvim standalone module
-      packages.nvim = inputs.nixvim.legacyPackages.${system}.makeNixvimWithModule {
+      packages.nvim = nixvim.makeNixvimWithModule module;
-        inherit pkgs;
-        module = standalone;
-      };
-
     };
 }

nvim/plugins.nix

@@ -5,7 +5,7 @@
   ...
 }:
 let
-  inherit (helpers) mkRaw;
+  inherit (helpers) mkRaw enableExceptInTests;
 in
 {
   config.plugins = {
@@ -160,6 +160,15 @@ in
       };
     };
     gitsigns.enable = true;
+    image.enable = enableExceptInTests;
+    jupytext = {
+      enable = true;
+      settings.custom_language_formatting.python = {
+        extension = "md";
+        style = "markdown";
+        force_ft = "markdown";
+      };
+    };
     lint = {
       enable = true;
       lintersByFt = {
@@ -214,6 +223,15 @@ in
       enable = true;
       settings.update_events = "TextChanged,TextChangedI";
     };
+    molten = {
+      enable = true;
+      settings = {
+        image_provider = "image.nvim";
+        virt_text_output = true;
+        molten_auto_open_output = false;
+        molten_virt_lines_off_by_1 = true;
+      };
+    };
     noice = {
       enable = true;
       lsp.override = {
@@ -245,6 +263,7 @@ in
         mode = "virtualtext";
       };
     };
+    otter.enable = true;
     rustaceanvim = {
       enable = true;
       # Install through rustup
@@ -260,6 +279,7 @@ in
     treesitter = {
       enable = true;
       settings = {
+        highlight.enable = true;
         indent.enable = true;
         incremental_election.enable = true;
       };

nvim/standalone.nix

@@ -62,6 +62,7 @@
       pkgs.unstable.typos
       pkgs.unstable.yamlfmt
     ];
+    extraPython3Packages = p: [ p.jupytext ];
     extraConfigLuaPre =
       # lua
       ''