Qt 5.15 will be EOL on May 26 so we should start switching away from it.
We already have issues with many of the previous versions and qmake on
legacy distros so we should cut that off.
I will add a Qt6 release build for Windows in another PR so it can be
tested. We should switch to it as the delivered build after the next
release and stop using Qt5 altogether in the CI in the release
afterwards (that would get rid of several build steps). We could leave
it so you could still try to build it but no longer support it so it is
up to the user to get it to work before removing it completely later on.
Building on #1874, commit adds user controls to choose
or edit style in cppcheck-gui ONLY. Commit does not
address CodeEditor style usage in triage app at this time.
Code Editor style can be altered from the added "Code Editor"
tab in the user preferences. The user has the option to select
default light, default dark, or to customize.
If user leaves the style set to light or dark defaults, this
will be reflected in the choices shown in the preferences
dialog.
User choice for Code Editor Style is saved in the cppcheck-gui
preferences under the heading "EditorStyle".