fix filter build error (#6214)

* fix filter build error

* add example heading

Author: jeff-allen-mongo

source/reference/operator/aggregation/filter.txt

@@ -155,35 +155,34 @@ Examples
 
 A collection ``sales`` has the following documents:
 
-.. io-code-block::
-   :copyable: true
-
-   .. input::
-      :language: javascript
+.. code-block:: javascript
 
-      db.sales.insertMany( [
-         {
-            _id: 0,
-            items: [
-               { item_id: 43, quantity: 2, price: 10, name: "pen" },
-               { item_id: 2, quantity: 1, price: 240, name: "briefcase" }
-            ]
-         },
-         {
-            _id: 1,
-            items: [
-               { item_id: 23, quantity: 3, price: 110, name: "notebook" },
-               { item_id: 103, quantity: 4, price: 5, name: "pen" },
-               { item_id: 38, quantity: 1, price: 300, name: "printer" }
-            ]
-         },
-         {
-            _id: 2,
-            items: [
-               { item_id: 4, quantity: 1, price: 23, name: "paper" }
-            ]
-         }
-      ] )
+   db.sales.insertMany( [
+      {
+         _id: 0,
+         items: [
+            { item_id: 43, quantity: 2, price: 10, name: "pen" },
+            { item_id: 2, quantity: 1, price: 240, name: "briefcase" }
+         ]
+      },
+      {
+         _id: 1,
+         items: [
+            { item_id: 23, quantity: 3, price: 110, name: "notebook" },
+            { item_id: 103, quantity: 4, price: 5, name: "pen" },
+            { item_id: 38, quantity: 1, price: 300, name: "printer" }
+         ]
+      },
+      {
+         _id: 2,
+         items: [
+            { item_id: 4, quantity: 1, price: 23, name: "paper" }
+         ]
+      }
+   ] )
+
+Filter Based on Number Comparison
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 The following example filters the ``items`` array to only include
 documents that have a ``price`` greater than or equal to ``100``: