Menu: act on a single keypress instead of waiting for Enter

Also stops Enter from quitting the menu (it used to share the quit branch with
q) and swallows the tail of an escape sequence, so one arrow key redraws once
rather than three times and never closes the menu.

po/cachy-auto-update.pot

@@ -134,7 +134,7 @@ msgstr ""
 msgid "Quit"
 msgstr ""
 
-msgid "Press Enter to continue..."
+msgid "Press any key to continue..."
 msgstr ""
 
 #. Commands

po/de.po

@@ -135,8 +135,8 @@ msgstr "Aktuelle Bedingungen anzeigen"
 msgid "Quit"
 msgstr "Beenden"
 
-msgid "Press Enter to continue..."
-msgstr "Zum Fortfahren Enter drücken …"
+msgid "Press any key to continue..."
+msgstr "Zum Fortfahren eine Taste drücken …"
 
 #. Commands
 msgid "Automatic updates are on."