Preview Style: Format module level docstring (#9725)

Co-authored-by: Micha Reiser <micha@reiser.io>

crates/ruff_python_formatter/src/preview.rs

@@ -74,3 +74,10 @@ pub(crate) const fn is_hex_codes_in_unicode_sequences_enabled(context: &PyFormat
 pub(crate) const fn is_multiline_string_handling_enabled(context: &PyFormatContext) -> bool {
     context.is_preview()
 }
+
+/// Returns `true` if the [`multiline_string_handling`](https://github.com/astral-sh/ruff/pull/9725) preview style is enabled.
+/// Black does not [`format docstrings`](https://github.com/psf/black/issues/3493) so we keep this
+/// preview for compatibility with Black.
+pub(crate) const fn is_format_module_docstring_enabled(context: &PyFormatContext) -> bool {
+    context.is_preview()
+}