pythongh-125832: Clarify comment for inlined comprehensions as per PEP-709 (python#126322)

* Fix comprehensions comment to inlined by pep 709

* Update spacing

Co-authored-by: RUANG (James Roy) <[email protected]>

* Add reference to PEP 709

---------

Co-authored-by: Carol Willing <[email protected]>
Co-authored-by: RUANG (James Roy) <[email protected]>
(cherry picked from commit 868bfcc)

Author: 3 people

Python/compile.c

@@ -5314,10 +5314,12 @@ compiler_call_helper(struct compiler *c, location loc,
     return SUCCESS;
 }
 
-
-/* List and set comprehensions and generator expressions work by creating a
-  nested function to perform the actual iteration. This means that the
-  iteration variables don't leak into the current scope.
+/* List and set comprehensions work by being inlined at the location where
+  they are defined. The isolation of iteration variables is provided by
+  pushing/popping clashing locals on the stack. Generator expressions work
+  by creating a nested function to perform the actual iteration.
+  This means that the iteration variables don't leak into the current scope.
+  See https://peps.python.org/pep-0709/ for additional information.
   The defined function is called immediately following its definition, with the
   result of that call being the result of the expression.
   The LC/SC version returns the populated container, while the GE version is