yapf: Add more detailed error message and TODO (flutter/engine#56458)

The yapf Python formatter is abandoned and only works with Python versions up to and including Python 3.11. upgraded, this will become more and more problematic. On some Linux distributions side-by-side python installations are unsupported, for example.

Issue: https://github.com/flutter/flutter/issues/158384

[C++, Objective-C, Java style guides]: https://github.com/flutter/engine/blob/main/CONTRIBUTING.md#style

engine/src/flutter/tools/yapf.sh

@@ -36,14 +36,22 @@ function follow_links() (
 SCRIPT_DIR=$(follow_links "$(dirname -- "${BASH_SOURCE[0]}")")
 SRC_DIR="$(cd "$SCRIPT_DIR/../.."; pwd -P)"
 YAPF_DIR="$(cd "$SRC_DIR/flutter/third_party/yapf"; pwd -P)"
+
+# TODO: https://github.com/flutter/flutter/issues/158384
+# Migrate to a supported Python formatter.
 if command -v python3.10 &> /dev/null; then
   PYTHON_EXEC="python3.10"
+elif command -v python3.11 &> /dev/null; then
+  PYTHON_EXEC="python3.11"
 else
   python3 -c "
 import sys
 version = sys.version_info
 if (version.major, version.minor) > (3, 11):
-    print(f'Error: python3 version {version.major}.{version.minor} is greater than 3.11.', file=sys.stderr)
+    print(f'Error: The yapf Python formatter requires Python version 3.11 or '
+          f'earlier. The installed python3 version is '
+          f'{version.major}.{version.minor}.',
+          file=sys.stderr)
     sys.exit(1)
 else:
     print(f'Using python3 version {version.major}.{version.minor}.')