[feat] Native Support for .njk Files in Beautify

[devvaannsh]

Describe the problem

Currently, the Beautify feature doesn't support the .njk file type out-of-the-box. Since Nunchucks (.njk) has its own templating syntax with directives like {{ }} and {% %}, it isn't recognized as standard HTML.

Current behavior:
Editing .njk files shows the Beautify option as greyed out/disabled.
Applying an HTML language override does not enable Beautify for these files.

Describe the solution you'd like

Enable the Beautify feature for .njk files by recognizing Nunchucks templating syntax.

Alternatives considered

No response

Additional context

No response