PHPLIB-786: Rename "Versioned API" to "Stable API" in docs (#888)

Author: jmikola

docs/includes/apiargs-MongoDBClient-method-construct-driverOptions.yaml

@@ -45,7 +45,7 @@ name: serverApi
 type: :php:`MongoDB\\Driver\\ServerApi <class.mongodb-driver-serverapi>`
 description: |
   Used to declare an API version on the client. See the
-  :manual:`Versioned API tutorial </tutorial/versioned-api>` for usage.
+  :manual:`Stable API tutorial </tutorial/stable-api>` for usage.
 
   .. versionadded:: 1.9
 interface: phpmethod

docs/tutorial.txt

@@ -15,4 +15,4 @@ Tutorials
    /tutorial/indexes
    /tutorial/tailable-cursor
    /tutorial/example-data
-   /tutorial/versioned-api
+   /tutorial/stable-api

docs/tutorial/versioned-api.txt docs/tutorial/stable-api.txtdocs/tutorial/versioned-api.txt renamed to docs/tutorial/stable-api.txt

@@ -1,6 +1,6 @@
-=============
-Versioned API
-=============
+==========
+Stable API
+==========
 
 .. default-domain:: mongodb
 
@@ -10,7 +10,7 @@ Versioned API
    :depth: 1
    :class: singlecol
 
-Declaring an API version
+Declaring an API Version
 ------------------------
 
 To declare an API version, pass a ``serverApi`` driver option when creating your
@@ -43,10 +43,9 @@ Strict API
 ----------
 
 By default, declaring an API version guarantees behavior for commands that are
-part of the versioned API, but does not forbid using commands that are not part
+part of the stable API, but does not forbid using commands that are not part
 of the API version. To only allow commands and options that are part of the
-versioned API, specify the ``strict`` option when creating the
-specify the ``strict`` option when creating the
+stable API, specify the ``strict`` option when creating the
 :php:`MongoDB\\Driver\\ServerApi <class.mongodb-driver-serverapi>` instance:
 
 .. code-block:: php
@@ -83,7 +82,7 @@ testing to ensure a smooth transition to a future API version.
 
    At the time of this writing, no part of API version "1" has been deprecated.
 
-Usage with the command helper
+Usage with the Command Helper
 -----------------------------
 
 When using the :phpmethod:`MongoDB\\Database::command()` method to run arbitrary