Move Glossify tip sanitizing to theme function

Feature request should happen to the 3.x branch.

Rebased.

We're using this for over a year now without any complains. Could someone do a final review of this to get this committed?

For the people who still need this for the 2.x branch I created a patch from the MR.

And one for 3.x for composer usage.

Merged, thanks!

Thank you!

Automatically closed - issue fixed for 2 weeks with no activity.