Breaking: #77826 - RTEHtmlArea Spellchecker eID removed 

See forge#77826

Description 

The RTEHtmlArea eID (rtehtmlarea_spellchecker) for using dynamic spellchecking has been removed.

RTEhtmlarea uses the Backend Routing API for Backend and Frontend Editing.

Impact 

Calling the eID script will result in a 404 error.

Affected Installations 

Installations which use the eID rtehtmlarea_spellchecker in a custom extension.