Apply suggestions from code review

Co-authored-by: Bénédikt Tran <10796600+picnixz@users.noreply.github.com>

Author: corona10

Doc/library/mmap.rst

@@ -334,9 +334,9 @@ To map anonymous memory, -1 should be passed as the fileno along with the length
       in ``/proc/<pid>/maps`` if the kernel supports the feature and :option:`-X dev <-X>` is passed
       to the Python or Python is built in :ref:`debug mode <debug-build>`
 
-      Availability: Linux kernel 5.17 or newer.
+      .. availability:: Linux >= 5.17
 
-      .. versionadded:: 3.15
+      .. versionadded:: next
 
    .. method:: size()
 

Doc/whatsnew/3.15.rst

@@ -581,7 +581,8 @@ mmap
   not be duplicated.
   (Contributed by Serhiy Storchaka in :gh:`78502`.)
 
-* :meth:`mmap.mmap.set_name` method added to annotation an anonymous memory map
+* Added the :meth:`mmap.mmap.set_name` method
+  to annotate an anonymous memory map
   if Linux kernel supports :manpage:`PR_SET_VMA_ANON_NAME <PR_SET_VMA(2const)>` (Linux 5.17 or newer).
   (Contributed by Donghee Na in :gh:`142419`.)