Updated CHANGELOG

Removed CHANGELOG entry

Moved conditional to helper method

This reverts commit 13e37a3e.

`refresh` was called, `refreshing` was set to true, but then because
`document.hidden` was true, `getContent` was never called, and
`refreshing` never got reset to `false`, which stopped polling entirely
until refresh.

Added a line to find the currently saved text and replace the markdown textarea text when cancelling

Updated CHANGELOG

Corrected the changes to store the markdown in a hidden input when edit starts and retrieve the original from that input when edit is cancelled

Replaced hidden input with form attribute

This reverts commit 3e991230.

# Conflicts:
#	app/models/project.rb

Closes #17778

To render emoji in the emoji bar of an issue or MR we actually need the emoji unicode and unicode info is stored in the emoji menu widget. That widget could only be visible if user clicks the "Add" button and there may not be a widget when posting emoji only comments. So this change will check existence of the widget and create it before posting the emoji if it's not exist to render it correctly.

Updated the JS to have a standard class with standard actions for each form
Created ability to have toolbar buttons that insert different prefixes dependant upon the data-prefix attribute

This should be done before .timeago() is called on the element

Also changed to allow the CSS to decide what should be hidden when editting