DOCSP-31019 document createEncryptedCollection method (#273)

Author: jmd-mongo

source/reference/methods.txt

@@ -801,13 +801,18 @@ Client-Side Field Level Encryption Methods
      </embedded-shell>`. 
 
 .. list-table::
-   :widths: 30 70
+   :widths: 40 60
    :header-rows: 1
 
    * - Method
 
      - Description
 
+   * - :upcoming:`ClientEncryption.createEncryptedCollection() 
+       </reference/method/ClientEncryption.createEncryptedCollection>`
+
+     - Creates a collection with encrypted fields.
+
    * - :method:`ClientEncryption.decrypt()`
 
      - Decrypts the specified ``encryptedValue`` if the current database