Apply consistent code block labels (#8563)

This ensures the python label is used for all python code blocks for
consistency.

## Test Plan

Visual inspection of all changes via git client ensuring no other
changes were made in error.

docs/tutorial.md

@@ -21,7 +21,7 @@ numbers
 
 ...where `numbers.py` contains the following code:
 
-```py
+```python
 from typing import Iterable
 
 import os
@@ -273,7 +273,7 @@ Found 3 errors.
 Any lint rule can be ignored by adding a `# noqa` comment to the line in question. For example,
 let's ignore the `UP035` rule for the `Iterable` import:
 
-```py
+```python
 from typing import Iterable  # noqa: UP035
 
 
@@ -294,7 +294,7 @@ Found 3 errors.
 If we want to ignore a rule for an entire file, we can add the line `# ruff: noqa: {code}` anywhere
 in the file, preferably towards the top, like so:
 
-```py
+```python
 # ruff: noqa: UP035
 from typing import Iterable