format-patch: add a blank line between notes and diffstat

The last line of the note text comes immediately before the diffstat
block, making the latter unnecessarily harder to view.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

log-tree.c

@@ -727,15 +727,16 @@ int log_tree_diff_flush(struct rev_info *opt)
 	}
 
 	if (opt->loginfo && !opt->no_commit_id) {
-		/* When showing a verbose header (i.e. log message),
-		 * and not in --pretty=oneline format, we would want
-		 * an extra newline between the end of log and the
-		 * output for readability.
-		 */
 		show_log(opt);
 		if ((opt->diffopt.output_format & ~DIFF_FORMAT_NO_OUTPUT) &&
 		    opt->verbose_header &&
 		    opt->commit_format != CMIT_FMT_ONELINE) {
+			/*
+			 * When showing a verbose header (i.e. log message),
+			 * and not in --pretty=oneline format, we would want
+			 * an extra newline between the end of log and the
+			 * diff/diffstat output for readability.
+			 */
 			int pch = DIFF_FORMAT_DIFFSTAT | DIFF_FORMAT_PATCH;
 			if (opt->diffopt.output_prefix) {
 				struct strbuf *msg = NULL;
@@ -743,11 +744,21 @@ int log_tree_diff_flush(struct rev_info *opt)
 					opt->diffopt.output_prefix_data);
 				fwrite(msg->buf, msg->len, 1, stdout);
 			}
-			if (!opt->shown_dashes) {
-				if ((pch & opt->diffopt.output_format) == pch)
-					printf("---");
-				putchar('\n');
-			}
+
+			/*
+			 * We may have shown three-dashes line early
+			 * between notes and the log message, in which
+			 * case we only want a blank line after the
+			 * notes without (an extra) three-dashes line.
+			 * Otherwise, we show the three-dashes line if
+			 * we are showing the patch with diffstat, but
+			 * in that case, there is no extra blank line
+			 * after the three-dashes line.
+			 */
+			if (!opt->shown_dashes &&
+			    (pch & opt->diffopt.output_format) == pch)
+				printf("---");
+			putchar('\n');
 		}
 	}
 	diff_flush(&opt->diffopt);