gh-97928: Partially restore the behavior of tkinter.Text.count() by default (GH-115031)

By default, it preserves an inconsistent behavior of older Python
versions: packs the count into a 1-tuple if only one or none
options are specified (including 'update'), returns None instead of 0.
Except that setting wantobjects to 0 no longer affects the result.

Add a new parameter return_ints: specifying return_ints=True makes
Text.count() always returning the single count as an integer
instead of a 1-tuple or None.