[3.13] GH-121970: Combine custom Pygments lexers into a package (GH-121976) (#122021)

GH-121970: Combine custom Pygments lexers into a package (GH-121976)
(cherry picked from commit 7431c3799efbd06ed03ee70b64420f45e83b3667)

Co-authored-by: Adam Turner <9087854+AA-Turner@users.noreply.github.com>
Co-authored-by: Hugo van Kemenade <1324225+hugovk@users.noreply.github.com>