Add tkinter Text methods edit_canundo() and edit_canredo()

[serhiy-storchaka]

Feature or enhancement

The Tk text widget supports the pathName edit canundo and pathName edit canredo subcommands, which report whether the undo and redo stacks are non-empty. tkinter currently wraps edit modified, edit redo, edit reset, edit separator and edit undo, but not edit canundo/edit canredo. They are only reachable through the generic, undocumented Text.edit() passthrough.

I propose adding two convenience methods to tkinter.Text:

• edit_canundo() — return True if undo is possible (the undo stack is not empty), False otherwise.
• edit_canredo() — return True if redo is possible (the redo stack is not empty), False otherwise.

Both return a proper bool.

Links to previous discussion

This is one of a few Tk text subcommands not yet wrapped by tkinter; sync/pendingsync are tracked separately.

Linked PRs

• gh-151674: Add tkinter Text.edit_canundo() and Text.edit_canredo() #151676