docs(python): add snippet for new_context fixture (#33392)

docs/src/test-runners-python.md

@@ -111,16 +111,21 @@ def test_visit_admin_dashboard(page: Page):
 
 If you're using VSCode with Pylance, these types can be inferred by enabling the `python.testing.pytestEnabled` setting so you don't need the type annotation.
 
-### Configure slow mo
+### Using multiple contexts
 
-Run tests with slow mo with the `--slowmo` argument.
+In order to simulate multiple users, you can create multiple [`BrowserContext`](./browser-contexts) instances.
 
-```bash
-pytest --slowmo 100
+```py title="test_my_application.py"
+from playwright.sync_api import Page, BrowserContext
+from pytest_playwright.pytest_playwright import CreateContextCallback
+
+def test_foo(page: Page, new_context: CreateContextCallback) -> None:
+    page.goto("https://example.com")
+    context = new_context()
+    page2 = context.new_page()
+    # page and page2 are in different contexts
 ```
 
-Slows down Playwright operations by 100 milliseconds.
-
 ### Skip test by browser
 
 ```py title="test_my_application.py"
@@ -198,7 +203,7 @@ def browser_context_args(browser_context_args):
     }
 ```
 
-### Device emulation
+### Device emulation / BrowserContext option overrides
 
 ```py title="conftest.py"
 import pytest