gh-148588: Add cross-ref link to __lazy_modules__ in NEWS, drop docs entry

Replace bare __lazy_modules__ in the 3.15.0a8 NEWS entry with
:attr:`module.__lazy_modules__` to link to the new attribute documentation.
Remove the separate docs NEWS entry; the archive entry serves as the record.

Author: johnslavik

Misc/NEWS.d/3.15.0a8.rst

@@ -186,7 +186,7 @@ dealing with contradictions in ``make_bottom``.
 .. section: Core and Builtins
 
 Ensure ``-X lazy_imports=none``` and ``PYTHON_LAZY_IMPORTS=none``` override
-``__lazy_modules__``. Patch by Hugo van Kemenade.
+:attr:`module.__lazy_modules__`. Patch by Hugo van Kemenade.
 
 ..