DOCSP-36781: fix aggregation references list (#871)

* DOCSP-36781: fix aggregation references list

* change from list to sentences

Author: rustagir

source/fundamentals/aggregation.txt

@@ -33,8 +33,9 @@ into assembly lines. Each station has specialized tools, such as
 drills and welders. The factory transforms and
 assembles the initial parts and materials into finished products.
 
-The **aggregation pipeline** is the assembly line, **aggregation stages** are the assembly stations, and
-**operator expressions** are the specialized tools.
+The **aggregation pipeline** is the assembly line, **aggregation
+stages** are the assembly stations, and **expression operators** are the
+specialized tools.
 
 Comparing Aggregation and Query Operations
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -72,13 +73,15 @@ Aggregation operations have some :manual:`limitations </core/aggregation-pipelin
 References
 ~~~~~~~~~~
 
-To learn more about aggregation concepts, see the following pages in the
-Server manual:
+To view a full list of expression operators, see :manual:`Aggregation
+Operators </reference/operator/aggregation/>` in the Server manual.
 
-- :manual:`Expression operators </reference/operator/aggregation/>`
-- :manual:`Aggregation pipeline </core/aggregation-pipeline/>`
-- :manual:`Aggregation stages </meta/aggregation-quick-reference/#stages>`
-- :manual:`Operator expressions </meta/aggregation-quick-reference/#operator-expressions>`
+To learn about assembling an aggregation pipeline and view examples, see
+:manual:`Aggregation Pipeline </core/aggregation-pipeline/>` in the
+Server manual.
+
+To learn more about creating pipeline stages, see :manual:`Aggregation
+Stages </reference/operator/aggregation-pipeline/>` in the Server manual.
 
 Runnable Examples
 -----------------