DOCS-11501: add links to $convert

Author: kay-kim

source/reference/operator/aggregation/convert.txt

@@ -731,7 +731,7 @@ The following table lists some conversion to date examples:
      - "Could not convert to type date."
 
 
-.. seealso:: :expression:`$toDate` operator, :expression:`$dateFromString()`
+.. seealso:: :expression:`$toDate` operator, :expression:`$dateFromString`
 
 .. _convert-to-objectId:
 

source/reference/operator/aggregation/toDate.txt

@@ -43,7 +43,7 @@ Definition
 
       { $convert: { input: <expression>, to: "date" } }
 
-   .. seealso:: :expression:`$convert`
+   .. seealso:: :expression:`$convert` and :expression:`$dateFromString`
 
 
 Behavior

source/reference/operator/aggregation/toString.txt

@@ -39,7 +39,7 @@ Definition
 
       { $convert: { input: <expression>, to: "string" } }
 
-   .. seealso:: :expression:`$convert`
+   .. seealso:: :expression:`$convert` and :expression:`$dateToString`
 
 
 Behavior

source/tutorial/model-monetary-data.txt

@@ -110,6 +110,12 @@ A collection's values can be transformed to the ``decimal`` type by
 performing a one-time transformation or by modifying application logic
 to perform the transformation as it accesses records.
 
+.. tip::
+
+   Alternative to the procedure outlined below, starting in version
+   4.0, you can use the :expression:`$convert` and its helper
+   :expression:`$toDecimal` operator to convert values to ``NumberDecimal()``.
+
 One-Time Collection Transformation
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^