fmt-merge-msg: make attribution into comment lines

The submaintainer credit is not something you can compute purely by
looking at the history and its shape, especially in the presense of
fast-forward merges, and this observation makes the information on
the "via" line unreliable.  Let's leave the final determination of
credits up to whoever is making the merge and show them as comments.

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

builtin/fmt-merge-msg.c

@@ -243,10 +243,10 @@ static void credit_people(struct strbuf *out,
 	const char *me;
 
 	if (kind == 'a') {
-		label = "\nBy ";
+		label = "\n# By ";
 		me = git_author_info(IDENT_NO_DATE);
 	} else {
-		label = "\nvia ";
+		label = "\n# Via ";
 		me = git_committer_info(IDENT_NO_DATE);
 	}
 

t/t6200-fmt-merge-msg.sh

@@ -102,8 +102,8 @@ test_expect_success '[merge] summary/log configuration' '
 	cat >expected <<-EOF &&
 	Merge branch ${apos}left${apos}
 
-	By Another Author (3) and A U Thor (2)
-	via Another Committer
+	# By Another Author (3) and A U Thor (2)
+	# Via Another Committer
 	* left:
 	  Left #5
 	  Left #4
@@ -149,8 +149,8 @@ test_expect_success 'merge.log=3 limits shortlog length' '
 	cat >expected <<-EOF &&
 	Merge branch ${apos}left${apos}
 
-	By Another Author (3) and A U Thor (2)
-	via Another Committer
+	# By Another Author (3) and A U Thor (2)
+	# Via Another Committer
 	* left: (5 commits)
 	  Left #5
 	  Left #4
@@ -166,8 +166,8 @@ test_expect_success 'merge.log=5 shows all 5 commits' '
 	cat >expected <<-EOF &&
 	Merge branch ${apos}left${apos}
 
-	By Another Author (3) and A U Thor (2)
-	via Another Committer
+	# By Another Author (3) and A U Thor (2)
+	# Via Another Committer
 	* left:
 	  Left #5
 	  Left #4
@@ -190,8 +190,8 @@ test_expect_success '--log=3 limits shortlog length' '
 	cat >expected <<-EOF &&
 	Merge branch ${apos}left${apos}
 
-	By Another Author (3) and A U Thor (2)
-	via Another Committer
+	# By Another Author (3) and A U Thor (2)
+	# Via Another Committer
 	* left: (5 commits)
 	  Left #5
 	  Left #4
@@ -207,8 +207,8 @@ test_expect_success '--log=5 shows all 5 commits' '
 	cat >expected <<-EOF &&
 	Merge branch ${apos}left${apos}
 
-	By Another Author (3) and A U Thor (2)
-	via Another Committer
+	# By Another Author (3) and A U Thor (2)
+	# Via Another Committer
 	* left:
 	  Left #5
 	  Left #4
@@ -238,8 +238,8 @@ test_expect_success 'fmt-merge-msg -m' '
 	cat >expected.log <<-EOF &&
 	Sync with left
 
-	By Another Author (3) and A U Thor (2)
-	via Another Committer
+	# By Another Author (3) and A U Thor (2)
+	# Via Another Committer
 	* ${apos}left${apos} of $(pwd):
 	  Left #5
 	  Left #4
@@ -271,8 +271,8 @@ test_expect_success 'setup: expected shortlog for two branches' '
 	cat >expected <<-EOF
 	Merge branches ${apos}left${apos} and ${apos}right${apos}
 
-	By Another Author (3) and A U Thor (2)
-	via Another Committer
+	# By Another Author (3) and A U Thor (2)
+	# Via Another Committer
 	* left:
 	  Left #5
 	  Left #4
@@ -396,8 +396,8 @@ test_expect_success 'merge-msg two tags' '
 	  Common #2
 	  Common #1
 
-	By Another Author (3) and A U Thor (2)
-	via Another Committer
+	# By Another Author (3) and A U Thor (2)
+	# Via Another Committer
 	* tag ${apos}tag-l5${apos}:
 	  Left #5
 	  Left #4
@@ -426,8 +426,8 @@ test_expect_success 'merge-msg tag and branch' '
 	  Common #2
 	  Common #1
 
-	By Another Author (3) and A U Thor (2)
-	via Another Committer
+	# By Another Author (3) and A U Thor (2)
+	# Via Another Committer
 	* left:
 	  Left #5
 	  Left #4