parsers: Add MDeiml/tree-sitter-markdown as markdown parser

Fixes #872

lua/nvim-treesitter/configs.lua

@@ -25,8 +25,7 @@ local builtin_modules = {
     enable = false,
     custom_captures = {},
     is_supported = function(lang)
-      -- FIXME(vigoux): markdown highlighting breaks everything for now
-      return lang ~= "markdown" and queries.has_highlights(lang)
+      return queries.has_highlights(lang)
     end,
     additional_vim_regex_highlighting = false,
   },

lua/nvim-treesitter/parsers.lua

@@ -433,13 +433,14 @@ list.hcl = {
   used_by = { "terraform" },
 }
 
--- FIXME(vigoux): markdown is broken for now
--- list.markdown = {
---   install_info = {
---     url = "https://github.com/ikatyang/tree-sitter-markdown",
---     files = { "src/parser.c", "src/scanner.cc" },
---   }
--- }
+list.markdown = {
+  install_info = {
+    url = "https://github.com/MDeiml/tree-sitter-markdown",
+    files = { "src/parser.c", "src/scanner.cc" },
+    branch = "main",
+  },
+  experimental = true,
+}
 
 list.tlaplus = {
   install_info = {