x11-toolkits/py-xlib: Update to 0.25

While I'm here:

• Fix license
• Set MASTER_SITES to CHEESESHOP
• Pet portlint

Changelog since 0.23-4:

• Fix increasing memory usage on display instantiation
• Fix protocol handling: correctly support explicit Unix connections and fix support fox macOS
• Fix xfixes example
• Fix a bunch of typos in the code / documentation
• Improve Python 3 support: fix events sub-code handling and possible crashes when unpacking text data
• Add support for error handlers to the Composite extension

NV-CONTROL extension

• Add first implementation by Roberto Leinardi

https://github.com/python-xlib/python-xlib/blob/0.25/CHANGELOG.md

PR: 236418
Submitted by: Olivier Duchateau <duchateau.olivier@gmail.com>
Approved by: miwi (mentor)
Differential Revision: https://reviews.freebsd.org/D19617