Allow prerelease branch for 3.14 (#93)

* Allow prerelease branch for 3.14

Ref #92.

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: m-aciek

completion.py

@@ -16,7 +16,9 @@ def branches_from_devguide(devguide_dir: Path) -> list[str]:
     p = devguide_dir.joinpath('include/release-cycle.json')
     data = json.loads(p.read_text())
     return [
-        branch for branch in data if data[branch]['status'] in ('bugfix', 'security')
+        branch
+        for branch in data
+        if data[branch]['status'] in ('bugfix', 'security', 'prerelease')
     ]