It's not a very well written example, using (largely unneed) hacks to
implement what it does. It's also misleading - the syntaxhighlighter
example is a better showcase for building a useful code editor.
Move it to manual tests.
Fixes: QTBUG-111025
Pick-to: 6.5
Change-Id: I405d41688235bf3e9a08373e716769f26d02fec6
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@qt.io>