Fix scheme count in `sysconfig` whatsnew entry (GH-94110)

(cherry picked from commit 9c47cf33)

Co-authored-by: Frank Dana <ferdnyc@gmail.com>

Doc/whatsnew/3.11.rst

@@ -694,7 +694,7 @@ sys
 sysconfig
 ---------
 
-* Two new :ref:`installation schemes <installation_paths>`
+* Three new :ref:`installation schemes <installation_paths>`
   (*posix_venv*, *nt_venv* and *venv*) were added and are used when Python
   creates new virtual environments or when it is running from a virtual
   environment.