keep external identifiers under 31 characters length

doc/sound.txt

@@ -331,7 +331,7 @@ activation.
      value that the platform's main() may have placed there earlier
      via its own call to assign_soundlib()]
 
-    2. init_sound_and_display_gamewindows()
+    2. init_sound_disp_gamewindows()
            ->  activate_chosen_soundlib() is called prior to
                displaying the game windows.
 

doc/window.txt

@@ -1027,11 +1027,11 @@ initoptions()			   /* read the resource file */
 init_nhwindows()		   /* initialize the window system */
 process_options(argc, argv)	   /* process command line options or equiv */
 if(save file is present) {
-  init_sound_and_display_gamewindows() /* init sound, create & display */
+  init_sound_disp_gamewindows() /* init sound, create & display */
   dorestore()			   /* restore old game; pline()s are OK */
 } else {
   player_selection()		   /* select a player type using a window */
-  init_sound_and_display_gamewindows() /* init sound, create & display  */
+  init_sound_disp_gamewindows() /* init sound, create & display  */
 }
 pline("Hello, welcome...");