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/diff.c b/src/diff.c
index 16389fd..88dc8a6 100644
--- a/src/diff.c
+++ b/src/diff.c
@@ -2764,7 +2764,7 @@
 	    {
 		// remember deleting the last line of the buffer
 		buf_empty = curbuf->b_ml.ml_line_count == 1;
-		ml_delete(lnum, FALSE);
+		ml_delete(lnum);
 		--added;
 	    }
 	    for (i = 0; i < dp->df_count[idx_from] - start_skip - end_skip; ++i)
@@ -2786,7 +2786,7 @@
 			// Added the first line into an empty buffer, need to
 			// delete the dummy empty line.
 			buf_empty = FALSE;
-			ml_delete((linenr_T)2, FALSE);
+			ml_delete((linenr_T)2);
 		    }
 		}
 	    }