DOCSP-29558 5.0 pushdown projection changes (#3189) (#3471)

* DOCSP-29558 5.0 pushdown projection changes

* IF feedback

* GH feedback

* punctuation

Author: ajhuh-mdb

source/release-notes/5.0.txt

@@ -573,6 +573,14 @@ collections.
 
 See :ref:`lookup-uncorrelated-subquery`.
 
+``$sort`` Stage: Performance Improvements
+`````````````````````````````````````````
+
+Starting in MongoDB 5.0, the :term:`query optimizer` pushes down the results of 
+a :pipeline:`$project` stage into the :pipeline:`$sort` stage. As a result, 
+``$sort`` operations can require less RAM when used with the ``project`` stage 
+and avoid ``Sort exceeded memory limit`` errors. 
+
 .. _5.0-rel-notes-auditing:
 
 Auditing