(DOCS-13987): Introduce updated query planner diagram (#2107) (#2154)

* Add new query planner diagram

* tech review feedback

* tech review feedback 2

* final changes

Author: davidhou17

source/core/query-plans.txt

@@ -25,6 +25,10 @@ evaluates candidate plans.
 The associated plan cache entry is used for subsequent queries with the
 same query shape.
 
+The following diagram illustrates the query planner logic:
+
+.. include:: /images/query-planner-logic.rst
+
 .. _cache-entry-state:
 
 Plan Cache Entry State

source/images/query-planner-logic.bakedsvg.svg

@@ -0,0 +1,3 @@
+.. figure:: /images/query-planner-logic.bakedsvg.svg
+   :alt: A diagram of MongoDB's query planner logic.
+   :figwidth: 700px