[Guides] MongoDB docs say live migration can't migrate a sharded cluster (#137)

Author: steveren

source/includes/migration_pr.rst

@@ -20,8 +20,7 @@
 
   If your deployment is currently a standalone instance, you must first
   :manual:`convert it to a replica set </tutorial/convert-standalone-to-replica-set>`.
-  Live migration of data from sharded clusters is not supported.
-
+  
 * (Optional) Enabled authentication on your source deployment.
 
   The migration process requires that authentication is enabled on your