[3.12] gh-120572: add missing parentheses in TypeIs documentation (GH-120573) (#120578)

Author: BlueGlassBlock

Doc/library/typing.rst

@@ -1394,8 +1394,8 @@ These can be used as types in annotations. They all support subscription using
                  print("Not a list of strings!")
 
    If ``is_str_list`` is a class or instance method, then the type in
-   ``TypeGuard`` maps to the type of the second parameter after ``cls`` or
-   ``self``.
+   ``TypeGuard`` maps to the type of the second parameter (after ``cls`` or
+   ``self``).
 
    In short, the form ``def foo(arg: TypeA) -> TypeGuard[TypeB]: ...``,
    means that if ``foo(arg)`` returns ``True``, then ``arg`` narrows from