[3.12] gh-103360: Add link in stdtypes.rst to escape sequences in lexical_analysis.rst (GH-103638) (GH-114907)

(cherry picked from commit d29f57f6036353b4e705a42637177442bf7e07e5)

Co-authored-by: Justin Williams <97240811+juswil@users.noreply.github.com>