Add Option to Capture Ctrl+S to Config Menu

[cyanff]

I often hit Ctrl+S out of paranoia. The "save .HTML" popping up is an annoyance.
It would be great if Ctrl+S could trigger either of these actions:

• Be ignored
• Trigger rustfmt

There was a duplicate issue here: #294
But it has been a few years since.
I'll gladly open a PR if adding this option seems appropriate.

[HKalbasi]

For the record, in monaco editor, Ctrl+S will run the code (similar to :w in ace vim mode).