Clear remaining tabs from gui-gtk-4.0 source files. Some other style fixes while touching the files.
Motivated mainly by the wish that gtk4-client codebase would be relatively clean base to start gtk4x/gtk5-client development (do this kind updates now once for gtk4-client, and not twice in the future for gtk4 + gtk-next clients)
Clear remaining tabs from gui-gtk-4.0 source files. Some other style fixes while touching the files.
Motivated mainly by the wish that gtk4-client codebase would be relatively clean base to start gtk4x/gtk5-client development (do this kind updates now once for gtk4-client, and not twice in the future for gtk4 + gtk-next clients)