Disable replacement in input fields

Created by: HughxDev

[Using the abbreviations M and SP to prevent a confusing bug report while the extension is enabled.]

It will trigger while I'm in the middle of typing a comment (as tested on Facebook), and then the cursor shifts to the start of the text, so I have to reposition my cursor and retype the word M and hopefully press Submit before it checks the page again. I want to submit the comment as M, so that people who don't have the extension installed will read it the way it's intended, but I don't mind it displaying as SP once it's posted.