Improve sentence structure

Author: matthurne

source/applications/aggregation.txt

@@ -251,8 +251,8 @@ all of the operators up to and including the first
 :agg:pipeline:`$group` or :agg:pipeline:`$sort` to each shard.
 [#match-sharding]_ Then, a second pipeline on the :program:`mongos`
 runs. This pipeline consists of the first :agg:pipeline:`$group` or
-:agg:pipeline:`$sort` and any remaining pipeline operators: this
-pipeline runs on the results received from the shards.
+:agg:pipeline:`$sort` and any remaining pipeline operators, and runs
+on the results received from the shards.
 
 The :program:`mongos` pipeline merges :agg:pipeline:`$sort` operations
 from the shards. The :agg:pipeline:`$group`, brings any “sub-totals”