Fixed Downloadables.add_directory.

Author: L'In20Cible

Diff for: addons/source-python/packages/source-python/stringtables/downloads.py

@@ -63,7 +63,7 @@ def add_directory(self, directory):
         """
         index = 0
         for index, file in enumerate(GAME_PATH.joinpath(directory).walkfiles(), 1):
-            self.add(file.replace(GAME_PATH, '').replace('\\', '/'))
+            self.add(file.replace(GAME_PATH, '').replace('\\', '/').lstrip('/'))
 
         return index