Add the ttk.Style.theme_styles() method

[serhiy-storchaka]

Tk 9.0 added the ttk::style theme styles ?themeName? subcommand, which returns the list of styles defined in a theme (the current theme if themeName is omitted). It is a clean introspection peer of the already-wrapped ttk::style theme names (ttk.Style.theme_names()).

tkinter does not yet wrap it. Proposal: add tkinter.ttk.Style.theme_styles(themename=None), returning a tuple of style names.

Linked PRs

• gh-151920: Add the ttk.Style.theme_styles() method #151921