[3.13] gh-106318: Add example for `str.endswith()` (GH-134523) (#135460)

gh-106318: Add example for `str.endswith()` (GH-134523)
(cherry picked from commit eed827ed091c6e55f11164046d287a76e30fbc0e)

Co-authored-by: Blaise Pabon <blaise@gmail.com>
Co-authored-by: Hugo van Kemenade <1324225+hugovk@users.noreply.github.com>