DOCSP-23597 Remove limitations (#50)

Author: Dave Cuthbert

source/reference/limitations.txt

@@ -29,7 +29,6 @@ General Limitations
 - The source and destination clusters must have the same Feature
   Compatibility Version.
 - The destination cluster must be empty.
-- DDL operations are currently not supported during syncing. 
 - ``mongosync`` does not validate that the clusters or the environment
   are properly configured. 
 - The primary shard cannot be :dbcommand:`reassigned <movePrimary>`