mlog: put the module docstring at the top of the file

Where it belongs. Otherwise it isn't rendered correctly

mesonbuild/mlog.py

@@ -11,6 +11,11 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+
+"""This is (mostly) a standalone module used to write logging
+information about Meson runs. Some output goes to screen,
+some to logging dir and some goes to both."""
+
 from __future__ import annotations
 
 import enum
@@ -35,10 +40,6 @@ if T.TYPE_CHECKING:
     TV_Loggable = T.Union[str, 'AnsiDecorator', StringProtocol]
     TV_LoggableList = T.List[TV_Loggable]
 
-"""This is (mostly) a standalone module used to write logging
-information about Meson runs. Some output goes to screen,
-some to logging dir and some goes to both."""
-
 def is_windows() -> bool:
     platname = platform.system().lower()
     return platname == 'windows'