Feature Request: Option to Render on Save

There is always the option to render with `⌘R`. However would it be possible to include an option to render on Save?

This would be particularly useful if the `Update preview automatically as you type` option has been turned off to get around the flicker.

Start by tracing the existing ⌘R render action and the save path, then inspect how the “Update preview automatically as you type” option is handled. Add a selectable render-on-save option that works when automatic typing updates are disabled, and verify that saving triggers the preview without changing manual rendering.

Written by the indexing model from the issue text.