display: do refresh the edit window when exiting from the help viewer

There are several cases (searching, replacing, spell checking, ...)
where exiting from the help viewer does NOT return the user to the
editing of the buffer.

This fixes https://savannah.gnu.org/bugs/?57295.

Bug existed since version 4.3, commit 5817e83e.

src/help.c

@@ -246,7 +246,6 @@ void do_help(void)
 	inhelp = FALSE;
 
 	curs_set(0);
-	refresh_needed = TRUE;
 
 	if (ISSET(NO_HELP)) {
 		currmenu = oldmenu;
@@ -261,7 +260,10 @@ void do_help(void)
 		browser_refresh();
 	else
 #endif
+	{
 		titlebar(NULL);
+		edit_refresh();
+	}
 }
 
 /* Allocate space for the help text for the current menu, and concatenate