Doc: Note that pydoc uses and prefers MANPAGER (#125362)

Co-authored-by: Adam Turner <[email protected]>

Author: mancellin

Doc/conf.py

@@ -199,6 +199,7 @@
     ('envvar', 'LC_TIME'),
     ('envvar', 'LINES'),
     ('envvar', 'LOGNAME'),
+    ('envvar', 'MANPAGER'),
     ('envvar', 'PAGER'),
     ('envvar', 'PATH'),
     ('envvar', 'PATHEXT'),

Doc/library/pydoc.rst

@@ -52,8 +52,9 @@ produced for that file.
    only execute code when a file is invoked as a script and not just imported.
 
 When printing output to the console, :program:`pydoc` attempts to paginate the
-output for easier reading.  If the :envvar:`PAGER` environment variable is set,
-:program:`pydoc` will use its value as a pagination program.
+output for easier reading.  If either the :envvar:`MANPAGER` or the
+:envvar:`PAGER` environment variable is set, :program:`pydoc` will use its
+value as a pagination program. When both are set, :envvar:`MANPAGER` is used.
 
 Specifying a ``-w`` flag before the argument will cause HTML documentation
 to be written out to a file in the current directory, instead of displaying text