Examples: move widgets/codeeditor into manual tests

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>

examples/widgets/doc/src/syntaxhighlighter.qdoc

@@ -219,10 +219,4 @@
     function. The QSyntaxHighlighter class also provides the \l
     {QSyntaxHighlighter::document()}{document()} function which
     returns the currently set document.
-
-    \section1 Other Code Editor Features
-
-    The \l{Code Editor Example} shows how to implement line
-    numbers and how to highlight the current line.
-
 */

examples/widgets/widgets/CMakeLists.txt

@@ -5,7 +5,6 @@ qt_internal_add_example(analogclock)
 qt_internal_add_example(calculator)
 qt_internal_add_example(calendarwidget)
 qt_internal_add_example(charactermap)
-qt_internal_add_example(codeeditor)
 qt_internal_add_example(digitalclock)
 qt_internal_add_example(groupbox)
 qt_internal_add_example(icons)

examples/widgets/widgets/widgets.pro

@@ -3,7 +3,6 @@ SUBDIRS       = analogclock \
                 calculator \
                 calendarwidget \
                 charactermap \
-                codeeditor \
                 digitalclock \
                 groupbox \
                 icons \

src/widgets/widgets/qplaintextedit.cpp

@@ -1187,8 +1187,7 @@ void QPlainTextEditPrivate::ensureViewportLayouted()
 
 
     \sa QTextDocument, QTextCursor, {Qt Widgets - Application Example},
-        {Code Editor Example}, {Syntax Highlighter Example},
-        {Rich Text Processing}
+        {Syntax Highlighter Example}, {Rich Text Processing}
 
 */