This enables spellcheck in Discord Message field. In some browsers Discord was updating spellcheck="false" leading to no spell check features in those boxes.

This fixes it for all servers and channels on Discord.com

Can be used for any other site by doing the following modifications:

Update site filter in the Heading of the script : Copy the @match directive line and add the domain wildcards you wish to cover.
Modify the class name of the filed being checked in SCEnable function.