Use module Augmentation to merge API types (#14082)

* Move display names into Jupyter Server Uri storage

* fix formatting

* Avoid validation of Jupyter Server providers

* Stop using display name from Uri storage

* Use module Augmentation to merge API types

* Fix linter

* fix formatting

src/api.proposed.d.ts

@@ -1,4 +1,4 @@
 // Copyright (c) Microsoft Corporation.
 // Licensed under the MIT License.
 
-export interface JupyterAPI {}
+//

src/api.pythonIntegration.d.ts

@@ -3,10 +3,12 @@
 
 import { PythonApi } from './platform/api/types';
 
-/**
- * These types are not required for any other extension, except for the Python extension.
- * Hence the reason to keep this separate. This way we can keep the API stable for other extensions (which would be the majority case).
- */
-export interface JupyterAPI {
-    registerPythonApi(pythonApi: PythonApi): void;
+declare module './api' {
+    /**
+     * These types are not required for any other extension, except for the Python extension.
+     * Hence the reason to keep this separate. This way we can keep the API stable for other extensions (which would be the majority case).
+     */
+    export interface JupyterAPI {
+        registerPythonApi(pythonApi: PythonApi): void;
+    }
 }