feat(null-ls): comment out "fish" builtins

because they trigger errors in :checkhealth

lua/plugins/null-ls.lua

@@ -0,0 +1,17 @@
+return {
+  {
+    "jose-elias-alvarez/null-ls.nvim",
+    opts = function()
+      local nls = require("null-ls")
+      return {
+        sources = {
+          -- nls.builtins.formatting.fish_indent,
+          -- nls.builtins.diagnostics.fish,
+          nls.builtins.formatting.stylua,
+          nls.builtins.formatting.shfmt,
+          -- nls.builtins.diagnostics.flake8,
+        },
+      }
+    end,
+  },
+}