[3.14] gh-134675: Add t-string prefixes to tokenizer module, lexical analysis doc, and add a test to make sure we catch this error in the future. (GH-134734) (#134739)

gh-134675: Add t-string prefixes to tokenizer module, lexical analysis doc, and add a test to make sure we catch this error in the future. (GH-134734)

* Add t-string prefixes to _all_string_prefixes, and add a test to make sure we catch this error in the future.

* Update lexical analysis docs for t-string prefixes.
(cherry picked from commit 08c78e02fab4a1c9c075637422d621f9c740959a)

Co-authored-by: Eric V. Smith <ericvsmith@users.noreply.github.com>