Fix sublime-color-scheme not applied to inline diff view
Fix sublime-color-scheme not applied to inline diff view

While fixing #1029 it was revealed that the generated color scheme was
not applied to the inline diff view at all.

Hence this commit modifies the `apply_new_theme()` method to ensure
only the basename of the generated scheme is set to the view's
"color_scheme" setting.

divmain/GitSavvy,divmain/GitSavvy,divmain/GitSavvy