dev-python: mass add longdescription lang="en"

Signed-off-by: Alessandro Barbieri <lssndrbarbieri@gmail.com>

dev-python/aspectlib/metadata.xml

@@ -6,7 +6,7 @@
     <email>lssndrbarbieri@gmail.com</email>
     <name>Alessandro Barbieri</name>
   </maintainer>
-  <longdescription>
+  <longdescription lang="en">
 An aspect-oriented programming, monkey-patch and decorators library. It is useful when changing behavior in existing code is desired. It includes tools for debugging and testing: simple mock/record and a complete capture/replay framework.
   </longdescription>
   <upstream>