gh-148321: use --quit-if-one-screen option for the pager (new REPL)

Currently, by passing --clear-screen (-c) to the pager --- small texts (like
few-sentences docstrings) are shown at top of the screen, just as big texts.

I believe it would be better to show this inline instead, not clearing
last session commands with output and so on.  BTW, this is the default
for git commands, e.g. git-log.  Of course, we loose on this way ability
to use pager for search, but terminal emulators usually have similar
capability on its own.

Author: skirpichev

Lib/_pyrepl/pager.py

@@ -138,7 +138,7 @@ def pipe_pager(text: str, cmd: str, title: str = '') -> None:
         '.'
         '?e (END):?pB %pB\\%..'
         ' (press h for help or q to quit)')
-    env['LESS'] = '-RcmPm{0}$PM{0}$'.format(prompt_string)
+    env['LESS'] = '-F-RmPm{0}$PM{0}$'.format(prompt_string)
     proc = subprocess.Popen(cmd, shell=True, stdin=subprocess.PIPE,
                             errors='backslashreplace', env=env)
     assert proc.stdin is not None