Uninstall does not clean up text filters

This module is a very nice attempt for dark mode fans. But it needs some work tmho...
And I'm not so sure that core will introduce this soon...

It should indeed be very nice if the dark mode was enabled when system or browser settings are in dark mode. Like the dark_mode_toggle module does. But perhaps more important, when enabled ones, it should stick to dark mode after a page refresh.

So I disabled the module. But after doing so, the button was still listed in the text formats and editors settings, breaking the rendering of the toolbar.

For now I just darkend the editor background...