Improve links in `ast.rst`

[sobolevn]

Bug report

There are two problems:

1. cpython/Doc/library/ast.rst

   Line 2539 in 15b3555

   `leoAst.py <https://leoeditor.com/appendices.html#leoast-py>`_ unifies the

   but https://leoeditor.com/appendices.html#leoast-py does not exist anymore, correct link is https://leo-editor.github.io/leo-editor/appendices.html#leoast-py
2. I also propose to remove parso, because it is no longer maintained for the last 4 years, no new syntax since 3.9? is supported: https://github.com/davidhalter/parso/graphs/contributors

Linked PRs

• gh-118100: Improve links in ast.rst #118101
• [3.12] gh-118100: Improve links in ast.rst (GH-118101) #118110

[hugovk]

Reminder: what's the next step after merging the PR and backport? :)

[sobolevn]

Reminder: what's the next step after merging the PR and backport? :)

Openning a new issue and a new PR! 😄