patch 8.2.0853: ml_delete() often called with FALSE argument

Problem:    ml_delete() often called with FALSE argument.
Solution:   Use ml_delete_flags(x, ML_DEL_MESSAGE) when argument is TRUE.
diff --git a/src/spell.c b/src/spell.c
index dab6aea..20826f3 100644
--- a/src/spell.c
+++ b/src/spell.c
@@ -3810,7 +3810,7 @@
 
     // Delete the empty line that we started with.
     if (curbuf->b_ml.ml_line_count > 1)
-	ml_delete(curbuf->b_ml.ml_line_count, FALSE);
+	ml_delete(curbuf->b_ml.ml_line_count);
 
     redraw_later(NOT_VALID);
 }