Adds types hints

tracim/tracim/lib/content.py

         item.revision_type = ActionDescription.EDITION
         return item
 
-    def update_file_data(self, item: Content, new_filename: str, new_mimetype: str, new_content) -> Content:
+    def update_file_data(self, item: Content, new_filename: str, new_mimetype: str, new_content: bytes) -> Content:
         item.owner = self._user
         item.file_name = new_filename
         item.file_mimetype = new_mimetype

tracim/tracim/lib/webdav/sql_resources.py

     def getLastModified(self) -> float:
         return mktime(self.content.updated.timetuple())
 
-    def getContent(self):
+    def getContent(self) -> typing.BinaryIO:
         filestream = compat.BytesIO()
         filestream.write(self.content.depot_file.file.read())
         filestream.seek(0)