patch 9.0.0590: after exiting Insert mode spelling not checked in next line

Problem:    After exiting Insert mode spelling is not checked in the next
            line.
Solution:   When spelling is enabled redraw the next line after exiting Insert
            mode in case the spell highlight needs updating.
diff --git a/src/drawline.c b/src/drawline.c
index 7e18ced..5413347 100644
--- a/src/drawline.c
+++ b/src/drawline.c
@@ -1125,10 +1125,7 @@
 #endif
 
 #ifdef FEAT_SPELL
-	if (wp->w_p_spell
-		&& *wp->w_s->b_p_spl != NUL
-		&& wp->w_s->b_langp.ga_len > 0
-		&& *(char **)(wp->w_s->b_langp.ga_data) != NULL)
+	if (spell_check_window(wp))
 	{
 	    // Prepare for spell checking.
 	    has_spell = TRUE;