Editor: Fix "Mark text changes" setting.

The revision markers are configured by the display
settings. There is no need to set them manually.

Task-number: QTCREATORBUG-13498
Change-Id: I99ee829d64dd23a7d24f13580a75c7c1666823f4
Reviewed-by: hjk <hjk121@nokiamail.com>

src/plugins/cppeditor/cppeditor.cpp

@@ -152,7 +152,6 @@ void CppEditorWidget::finalizeInitialization()
     d->m_cppEditorDocument = qobject_cast<CppEditorDocument *>(textDocument());
 
     setLanguageSettingsId(CppTools::Constants::CPP_SETTINGS_ID);
-    setRevisionsVisible(true);
 
     // function combo box sorting
     connect(CppEditorPlugin::instance(), &CppEditorPlugin::outlineSortingChanged,

src/plugins/texteditor/texteditor.cpp

@@ -7215,7 +7215,6 @@ bool TextEditorWidget::isMissingSyntaxDefinition() const
 // The remnants of PlainTextEditor.
 void TextEditorWidget::setupAsPlainEditor()
 {
-    setRevisionsVisible(true);
     setMarksVisible(true);
     setLineSeparatorsAllowed(true);