[BUG][FIX] In SqueakCore Workspace when you try to do some which sends toggleStyling raises DNU

And the cause is

toggleStyling

    shouldStyle := self shouldStyle not.
    " Ugly hack, to restyle our contents. "
    self codeTextMorph in: [ :codeTextMorph |
        codeTextMorph setText:
            codeTextMorph textMorph text asString asText ]

StringHolder>#codeTextMorph   was removed as part of services.
So my idea is move to user edits category and put new versions of touched
packages, what you think ?

Edgar