Add %B' in format strings for raw commit body in git log' and friends

Also update the documentation text and add a test.

Signed-off-by: Eli Barzilay <eli@barzilay.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/pretty-formats.txt

@@ -123,6 +123,7 @@ The placeholders are:
 - '%s': subject
 - '%f': sanitized subject line, suitable for a filename
 - '%b': body
+- '%B': raw body (unwrapped subject and body)
 - '%N': commit notes
 - '%gD': reflog selector, e.g., `refs/stash@\{1\}`
 - '%gd': shortened reflog selector, e.g., `stash@\{1\}`

pretty.c

@@ -797,6 +797,10 @@ static size_t format_commit_one(struct strbuf *sb, const char *placeholder,
 	case 'e':	/* encoding */
 		strbuf_add(sb, msg + c->encoding.off, c->encoding.len);
 		return 1;
+	case 'B':	/* raw body */
+		/* message_off is always left at the initial newline */
+		strbuf_addstr(sb, msg + c->message_off + 1);
+		return 1;
 	}
 
 	/* Now we need to parse the commit message. */

t/t6006-rev-list-format.sh

@@ -101,6 +101,15 @@ commit 131a310eb913d107dd3c09a65d1651175898735d
 commit 86c75cfd708a0e5868dc876ed5b8bb66c80b4873
 EOF
 
+test_format raw-body %B <<'EOF'
+commit 131a310eb913d107dd3c09a65d1651175898735d
+changed foo
+
+commit 86c75cfd708a0e5868dc876ed5b8bb66c80b4873
+added foo
+
+EOF
+
 test_format colors %Credfoo%Cgreenbar%Cbluebaz%Cresetxyzzy <<'EOF'
 commit 131a310eb913d107dd3c09a65d1651175898735d
 foobarbazxyzzy