gh-119205: Fix autocompletion bug in new repl

[koxudaxi]

If the interpreter shows a warning, the new repl prompt cursor moves after the warning.

• Issue: gh-119205

[ghost]

All commit authors signed the Contributor License Agreement.

[bedevere-app[bot]]

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[lysnikolaou]

@koxudaxi Can you please rebase onto main and move the tests to the newly created test_pyrepl directory?

[bedevere-app[bot]]

Most changes to Python require a NEWS entry. Add one using the blurb_it web app or the blurb command-line tool.

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[koxudaxi]

@ambv @lysnikolaou Thank you for reviewing and rebasing my PR. I apologize I was moving to Pittsburgh airport from the conference center.

[ambv]

@koxudaxi let the tests complete, don't rebase unless there are conflicts.

[bedevere-bot]

:warning::warning::warning: Buildbot failure :warning::warning::warning:

Hi! The buildbot AMD64 Debian root 3.x has failed when building commit 506b1a3ff66a41c72d205c8e4cba574e439d8e76.

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/all/#builders/345/builds/8076) and take a look at the build logs.
4. Check if the failure is related to this commit (506b1a3ff66a41c72d205c8e4cba574e439d8e76) 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/all/#builders/345/builds/8076

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

Click to see traceback logs

Note: switching to '506b1a3ff66a41c72d205c8e4cba574e439d8e76'.

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Turn off this advice by setting config variable advice.detachedHead to false

HEAD is now at 506b1a3ff6 gh-119205: Fix autocompletion bug in new repl (#119229)
Switched to and reset branch 'main'

configure: WARNING: no system libmpdecimal found; falling back to bundled libmpdecimal (deprecated and scheduled for removal in Python 3.15)
configure: WARNING: pkg-config is missing. Some dependencies may not be detected correctly.

make: *** wait: No child processes.  Stop.
make: *** Waiting for unfinished jobs....
make: *** wait: No child processes.  Stop.

Cannot open file '/root/buildarea/3.x.angelico-debian-amd64/build/test-results.xml' for upload

[ambv]

The buildbot failure is an unrelated timeout:

command timed out: 1800 seconds without output running [b'make', b'buildbottest', b'TESTOPTS=-j2 --junit-xml test-results.xml ${BUILDBOT_TESTOPTS}', b'TESTPYTHONOPTS=', b'TESTTIMEOUT=1200'], attempting to kill

[miss-islington-app[bot]]

Thanks @koxudaxi for the PR, and @ambv for merging it 🌮🎉.. I'm working now to backport this PR to: 3.13. 🐍🍒⛏🤖 I'm not a witch! I'm not a witch!

[bedevere-app[bot]]

GH-119407 is a backport of this pull request to the 3.13 branch.