Issue #23921: Standardized documentation whitespace formatting.
Original patch by James Edwards.
diff --git a/Doc/tutorial/controlflow.rst b/Doc/tutorial/controlflow.rst
index 8ffaf3f..2af60d0 100644
--- a/Doc/tutorial/controlflow.rst
+++ b/Doc/tutorial/controlflow.rst
@@ -284,7 +284,7 @@
 It is simple to write a function that returns a list of the numbers of the
 Fibonacci series, instead of printing it::
 
-   >>> def fib2(n): # return Fibonacci series up to n
+   >>> def fib2(n):  # return Fibonacci series up to n
    ...     """Return a list containing the Fibonacci series up to n."""
    ...     result = []
    ...     a, b = 0, 1