vim: highlight markdown-style code fences

e.g.
```tex
did you know $\frac29 == \frac4{18}$ ?
```

modules/universal/env/home-manager.nix

@@ -386,6 +386,14 @@ in
             vim-surround
             # docs: fzf-vim (fuzzy finder): https://github.com/junegunn/fzf.vim
             fzf-vim
+            ({
+              plugin = vim-SyntaxRange;
+              type = "viml";
+              config = ''
+                " enable markdown-style codeblock highlighting for tex code
+                autocmd BufEnter * call SyntaxRange#Include('```tex', '```', 'tex', 'NonText')
+              '';
+            })
             # nabla renders inline math in any document, but it's buggy.
             #   https://github.com/jbyuki/nabla.nvim
             # ({
@@ -396,6 +404,7 @@ in
             #   '';
             # })
             # treesitter syntax highlighting: https://nixos.wiki/wiki/Tree_sitters
+            # 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
             ({
@@ -405,7 +414,12 @@ in
                 require'nvim-treesitter.configs'.setup {
                   highlight = {
                     enable = true,
-                    disable = {}
+                    -- disable treesitter on Rust so that we can use SyntaxRange
+                    -- and leverage TeX rendering in rust projects
+                    disable = { "rust", "tex", "latex" },
+                    -- disable = { "tex", "latex" },
+                    -- true to also use builtin vim syntax highlighting when treesitter fails
+                    additional_vim_regex_highlighting = false
                   },
                   incremental_selection = {
                     enable = true,