patch 8.1.1757: text added with appendbufline() isn't displayed

Problem:    Text added with appendbufline() to another buffer isn't displayed.
Solution:   Update topline. (partly by Christian Brabandt, closes #4718)
diff --git a/src/evalfunc.c b/src/evalfunc.c
index 685e2f1..c0b6788 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -1401,12 +1401,7 @@
 	    if (wp->w_buffer == buf && wp->w_cursor.lnum > append_lnum)
 		wp->w_cursor.lnum += added;
 	check_cursor_col();
-
-#ifdef FEAT_JOB_CHANNEL
-	if (bt_prompt(curbuf) && (State & INSERT))
-	    // show the line with the prompt
-	    update_topline();
-#endif
+	update_topline();
     }
 
     if (!is_curbuf)