change wording

Author: shuangela

source/reference/collection-level-filtering.txt

@@ -85,7 +85,7 @@ Filters have the following syntax:
        }
     ]
 
-To learn more about syntax for ``regex-pattern`` and options for regular
+To learn more about syntax for ``pattern`` and ``options`` for regular
 expression filtering, see :ref:`c2c-filter-regex`. 
 
 Filters must include either the ``database`` field or the ``databaseRegex`` field.

source/reference/collection-level-filtering/filter-regex.txt

@@ -36,8 +36,7 @@ you can use regular expressions:
       }
    }
 
-The regular express pattern you pass into a filter must follow the :query:`regular
-expression <$regex>` syntax supported by the MongoDB server.
+The regular express pattern you pass into a filter must follow the :query:`regex <$regex>` syntax supported by the MongoDB server.
 
 The following ``options`` are available for use with regular
 expressions: