gh-81039: Add small example of f-string's "=}" to tutorial (gh-92291) (gh-96989)

(cherry picked from commit 4b81139aac3fa11779f6eedb6e621bde29e64b30)

Co-authored-by: Stanley <46876382+slateny@users.noreply.github.com>

Co-authored-by: Stanley <46876382+slateny@users.noreply.github.com>