Add mcp.types as a permanent alias for mcp_types (#3190)

docs/advanced/extensions.md

@@ -128,7 +128,7 @@ The same file's `main()` is the whole client story, both halves of it:
 The one interceptive hook. Override `intercept_tool_call` to observe, short-circuit,
 or veto a tool call:
 
-```python title="server.py" hl_lines="18-25"
+```python title="server.py" hl_lines="17-24"
 --8<-- "docs_src/extensions/tutorial005.py"
 ```
 
@@ -158,7 +158,7 @@ A **client extension** is the same contract from the consuming side: a bundle of
 client-side behaviour behind one identifier. Pass instances to
 `Client(extensions=[...])` and call tools normally:
 
-```python title="client.py" hl_lines="67-69"
+```python title="client.py" hl_lines="66-68"
 --8<-- "docs_src/extensions/tutorial006.py"
 ```
 
@@ -188,7 +188,7 @@ client = Client(mcp, extensions=[advertise("com.example/search")])
 Subclass `ClientExtension` and override only what you need. Three contribution
 kinds, each with a default: `settings()`, `claims()`, and `notifications()`.
 
-```python title="client.py" hl_lines="18-19 44-45 47-48"
+```python title="client.py" hl_lines="17-18 43-44 46-47"
 --8<-- "docs_src/extensions/tutorial006.py"
 ```
 
@@ -226,12 +226,12 @@ claimed shape reaching a session-tier caller raises `UnexpectedClaimedResult`.
 ### Extension verbs
 
 An extension's own request methods need no client-side registration. A vendor request
-type subclasses `mcp_types.Request` and goes through `client.session.send_request`,
+type subclasses `mcp.types.Request` and goes through `client.session.send_request`,
 as in [Serving your own methods](#serving-your-own-methods). One addition: when a
 params key must ride the `Mcp-Name` header (extension specs such as tasks require
 this for their verbs), the request type declares `name_param`:
 
-```python title="client.py" hl_lines="23-26 47-48"
+```python title="client.py" hl_lines="22-25 46-47"
 --8<-- "docs_src/extensions/tutorial007.py"
 ```