Fix registry query flag validation

[CAD97]

Description

Fix the Windows-only registry query command to properly validate that only one hive selection flag (e.g. --hkcu, --hklm). Code to emit this error existed previously, but was accidentally unreachable due to the code structure.

• fixes registry query fails to emit error for multiple hive flags #10646

User-Facing Changes

• registry query now errors if more than one hive selection flag (e.g. --hkcu, --hklm) is used. This was always intended to be an error, but previous versions always used the first flag based on an internal check order instead.

Tests + Formatting

• toolkit check pr

Documentation

registry query doesn't seem to be in the command reference yet, actually.

[CAD97]

Fixed the silly mistake, now builds and passes tests.

Side note: you might want to change the workflow approval requirement from "Require approval for first-time contributors" to "Require approval for first-time contributors who are new to GitHub."

[fdncred]

Thanks for fixing my crappy code :-)