[DRE-maint] Bug#1018034: Exact error messages and workaround to go back to source editor

[Fabien (Debian)]

Message displayed in page:

   "An error occurred while trying to render the content editor. Please 
try again later. [Retry]"

Errors in JS console (Firefox 103):

   "RangeError: Adding different instances of a keyed plugin (plugin$)"

   "TypeError: t.contentEditor is undefined"


Workaround:

Since JS is broken, "Edit source" button doesn't work anymore once the 
bug is happening.

Thankfully, it's enough (in Firefox) to
- press F12 to display debug tools
- go to the "Storage editor" in "Local Storage"
- find "gl-wiki-content-editor-enabled" entry and change its value to 
"false"