nixpkgs/neovim: ensure help files are detected

.config/nixpkgs/neovim/neovim.nix

@@ -88,6 +88,15 @@ let
       set runtimepath=${placeholder "out"}/lib,$VIMRUNTIME
       set packpath=${placeholder "out"}/lib
 
+      lua <<EOF
+      -- make sure docs in our packpath are marked as help
+      vim.filetype.add({
+        pattern = {
+          [vim.o.packpath:gsub('[%.%-]', '%%%0') .. '/pack/.*/doc/.*%.txt'] = 'help'
+        }
+      })
+      EOF
+
       ${initText}
     '';