fix(registry): export Padding from registry.checks

Author: Nytelife26

proselint/registry/checks/__init__.py

@@ -123,3 +123,6 @@ def check(self, text: str) -> Iterator[CheckResult]:
     def check_with_flags(self, text: str) -> Iterator[CheckResult]:
         """Apply the check over `text`, including specified `CheckFlags`."""
         return self.flags.apply(self.check(text), len(text))
+
+
+__all__ = ("Check", "CheckFlags", "CheckResult", "LintResult", "Padding")