[3.13] gh-139065: Fix trailing space before long word in textwrap (GH-139070) (GH-139903)

Fix trailing space before a wrapped long word if the line length with
a space is exactly "width".
(cherry picked from commit 1c598e04361dbfc9cf465f3a02f83715c11b028c)

Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>