[3.13] gh-101100: Fix sphinx warnings in Doc/library/platform.rst (GH-136562) (GH-136598)

(cherry picked from commit 47b01da)

Co-authored-by: Weilin Du <108666168+LamentXU123@users.noreply.github.com>

Author: miss-islington

Doc/library/platform.rst

@@ -176,8 +176,8 @@ Cross platform
    :attr:`processor` is resolved late, on demand.
 
    Note: the first two attribute names differ from the names presented by
-   :func:`os.uname`, where they are named :attr:`sysname` and
-   :attr:`nodename`.
+   :func:`os.uname`, where they are named :attr:`!sysname` and
+   :attr:`!nodename`.
 
    Entries which cannot be determined are set to ``''``.
 

Doc/tools/.nitignore

@@ -27,7 +27,6 @@ Doc/library/multiprocessing.rst
 Doc/library/optparse.rst
 Doc/library/os.rst
 Doc/library/pickletools.rst
-Doc/library/platform.rst
 Doc/library/profile.rst
 Doc/library/pyexpat.rst
 Doc/library/resource.rst