fsck: document msg-id

The documentation lacks mention of specific <msg-id> that are supported.
While git-help --config will display a list of these options, often
developers' first instinct is to consult the git docs to find valid
config values.

Add a list of fsck error messages, and link to it from the git-fsck
documentation.

Signed-off-by: John Cai <johncai86@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/fsck.h b/fsck.h
index 1d7c38f268..6fbce68ad6 100644
--- a/fsck.h
+++ b/fsck.h
@@ -13,6 +13,12 @@ enum fsck_msg_type {
 	FSCK_WARN,
 };
 
+/*
+ * Documentation/fsck-msgids.txt documents these; when
+ * modifying this list in any way, make sure to keep the
+ * two in sync.
+ */
+
 #define FOREACH_FSCK_MSG_ID(FUNC) \
 	/* fatal errors */ \
 	FUNC(NUL_IN_HEADER, FATAL) \