gh-128874: Fix the documentation for blurb 2.0

[vstinner]

• Issue: Building the documentation fails with newly released blurb 2.0 #128874

[hugovk]

Thanks!

For reference, this is the extra validation added in python/blurb#35.

[miss-islington-app]

Thanks @vstinner for the PR 🌮🎉.. I'm working now to backport this PR to: 3.12, 3.13.
🐍🍒⛏🤖 I'm not a witch! I'm not a witch!

[bedevere-app]

GH-128877 is a backport of this pull request to the 3.13 branch.

[bedevere-app]

GH-128878 is a backport of this pull request to the 3.12 branch.

[miss-islington-app]

Thanks @vstinner for the PR 🌮🎉.. I'm working now to backport this PR to: 3.11.
🐍🍒⛏🤖

[bedevere-app]

GH-128879 is a backport of this pull request to the 3.11 branch.

[bedevere-app]

GH-128890 is a backport of this pull request to the 3.10 branch.

[bedevere-bot]

⚠️⚠️⚠️ Buildbot failure ⚠️⚠️⚠️

Hi! The buildbot aarch64 Fedora Stable Refleaks 3.11 has failed when building commit a83a7cf.

What do you need to do:

1. Don't panic.
2. Check the buildbot page in the devguide if you don't know what the buildbots are or how they work.
3. Go to the page of the buildbot that failed (https://buildbot.python.org/#/builders/1021/builds/17) and take a look at the build logs.
4. Check if the failure is related to this commit (a83a7cf) or if it is a false positive.
5. If the failure is related to this commit, please, reflect that on the issue and make a new Pull Request with a fix.

You can take a look at the buildbot page here:

https://buildbot.python.org/#/builders/1021/builds/17

Failed tests:

• test_socket
• test_threading

Failed subtests:

• test_BoundedSemaphore_limit - test.test_threading.ThreadTests.test_BoundedSemaphore_limit
• testStream - test.test_socket.ThreadedVSOCKSocketStreamTest.testStream

Summary of the results of the build (if available):

==

Click to see traceback logs

Traceback (most recent call last):
  File "/home/buildbot/buildarea/3.11.cstratak-fedora-stable-aarch64.refleak/build/Lib/threading.py", line 1002, in _bootstrap
    self._bootstrap_inner()
  File "/home/buildbot/buildarea/3.11.cstratak-fedora-stable-aarch64.refleak/build/Lib/threading.py", line 1040, in _bootstrap_inner
    _sys.settrace(_trace_hook)
RuntimeError: Cannot install a trace function while another trace function is being installed
FAIL


Traceback (most recent call last):
  File "/home/buildbot/buildarea/3.11.cstratak-fedora-stable-aarch64.refleak/build/Lib/test/test_socket.py", line 346, in _setUp
    self.__setUp()
  File "/home/buildbot/buildarea/3.11.cstratak-fedora-stable-aarch64.refleak/build/Lib/test/test_socket.py", line 489, in setUp
    self.conn, self.connaddr = self.serv.accept()
                               ^^^^^^^^^^^^^^^^^^
  File "/home/buildbot/buildarea/3.11.cstratak-fedora-stable-aarch64.refleak/build/Lib/socket.py", line 294, in accept
    fd, addr = self._accept()
               ^^^^^^^^^^^^^^
TimeoutError: timed out


Traceback (most recent call last):
  File "/home/buildbot/buildarea/3.11.cstratak-fedora-stable-aarch64.refleak/build/Lib/test/test_threading.py", line 907, in test_BoundedSemaphore_limit
    self.assertRaises(ValueError, bs.release)
AssertionError: ValueError not raised by release


Traceback (most recent call last):
  File "/home/buildbot/buildarea/3.11.cstratak-fedora-stable-aarch64.refleak/build/Lib/test/test_socket.py", line 334, in raise_queued_exception
    raise self.queue.get()
  File "/home/buildbot/buildarea/3.11.cstratak-fedora-stable-aarch64.refleak/build/Lib/test/test_socket.py", line 358, in clientRun
    self.clientSetUp()
  File "/home/buildbot/buildarea/3.11.cstratak-fedora-stable-aarch64.refleak/build/Lib/test/test_socket.py", line 497, in clientSetUp
    self.cli.connect((cid, VSOCKPORT))
OSError: [Errno 19] No such device

[bedevere-bot]

⚠️⚠️⚠️ Buildbot failure ⚠️⚠️⚠️

Hi! The buildbot AMD64 Fedora Stable Refleaks 3.11 has failed when building commit a83a7cf.

What do you need to do:

1. Don't panic.
2. Check the buildbot page in the devguide if you don't know what the buildbots are or how they work.
3. Go to the page of the buildbot that failed (https://buildbot.python.org/#/builders/1027/builds/796) and take a look at the build logs.
4. Check if the failure is related to this commit (a83a7cf) or if it is a false positive.
5. If the failure is related to this commit, please, reflect that on the issue and make a new Pull Request with a fix.

You can take a look at the buildbot page here:

https://buildbot.python.org/#/builders/1027/builds/796

Failed tests:

• test_socket

Failed subtests:

• testStream - test.test_socket.ThreadedVSOCKSocketStreamTest.testStream

Summary of the results of the build (if available):

==

Click to see traceback logs

Traceback (most recent call last):
  File "/home/buildbot/buildarea/3.11.cstratak-fedora-stable-x86_64.refleak/build/Lib/test/test_socket.py", line 334, in raise_queued_exception
    raise self.queue.get()
  File "/home/buildbot/buildarea/3.11.cstratak-fedora-stable-x86_64.refleak/build/Lib/test/test_socket.py", line 358, in clientRun
    self.clientSetUp()
  File "/home/buildbot/buildarea/3.11.cstratak-fedora-stable-x86_64.refleak/build/Lib/test/test_socket.py", line 497, in clientSetUp
    self.cli.connect((cid, VSOCKPORT))
OSError: [Errno 19] No such device


Traceback (most recent call last):
  File "/home/buildbot/buildarea/3.11.cstratak-fedora-stable-x86_64.refleak/build/Lib/test/test_socket.py", line 346, in _setUp
    self.__setUp()
  File "/home/buildbot/buildarea/3.11.cstratak-fedora-stable-x86_64.refleak/build/Lib/test/test_socket.py", line 489, in setUp
    self.conn, self.connaddr = self.serv.accept()
                               ^^^^^^^^^^^^^^^^^^
  File "/home/buildbot/buildarea/3.11.cstratak-fedora-stable-x86_64.refleak/build/Lib/socket.py", line 294, in accept
    fd, addr = self._accept()
               ^^^^^^^^^^^^^^
TimeoutError: timed out

[vstinner]

Hi! The buildbot AMD64 Fedora Stable Refleaks 3.11 has failed when building commit a83a7cf.
testStream - test.test_socket.ThreadedVSOCKSocketStreamTest.testStream

I created PR gh-129171 for that.