Clarify the vMCP CLI endpoint (#886)

Signed-off-by: Dan <dan@stacklok.com>

Author: danbarr

docs/toolhive/guides-vmcp/local-cli.mdx

@@ -68,9 +68,9 @@ just a group name:
 thv vmcp serve --group my-group
 ```
 
-By default, the server binds to `127.0.0.1:4483`. Point your MCP client at
-`http://127.0.0.1:4483` to access all tools from the group through a single
-endpoint.
+By default, the server binds to `127.0.0.1:4483` using the Streamable HTTP
+transport protocol. Point your MCP client at `http://127.0.0.1:4483/mcp` to
+access all tools from the group through a single endpoint.
 
 :::note[Loopback-only]