Stop rerendering mathjax on every keypress

Bug Report

Description

When editing messages Mathjax is rerendered on every keypress.

Behavior

Expected: Mathjax should be rerendered on every edit, potentially with a 1-2 seconds timeout.

Actual: Navigation with arrows also triggers a rerender.

Steps to Reproduce

1. Start editing a message with a live preview
2. Add e.g.
   x=0
   to the message.
3. Press an arrow key
4. Observe that mathjax is rerendering

Additional Information

This is a low impact issue

changed the description

Hi @akhmerov, thanks for submitting this. Can you let me know which page (URL) is affected by this?

Any field with a rich preview. For example, the referee report form, the author response, etc.

closed with commit 9694b491

assigned to @gkatsikas

mentioned in commit 9694b491