Add docs for the 'references' header

* git-email.el (git-email-headers):

1 files changed, 25 insertions, 1 deletions

diff --git a/git-email.el b/git-email.el
index 8af2da6..5a12e1c 100644
--- a/git-email.el
+++ b/git-email.el
@@ -53,7 +53,31 @@
   '("subject" "from" "in-reply-to" "message-id")
   "List of headers that should get inserted into the message buffer.
 The 'to' address will always be inserted based on the 'sendemail.to' variable
-in you git config.  If the variable is not set, the 'to' address will be empty."
+in you git config.  If the variable is not set, the 'to' address will be empty.
+
+To insert the 'references' header, you have to set `message-header-format-alist'
+to something like this.
+
+  (setq message-header-format-alist
+  '((From)
+    (Newsgroups)
+    (To)
+    (Cc)
+    (Subject)
+    (In-Reply-To)
+    (Fcc)
+    (Bcc)
+    (Date)
+    (Organization)
+    (Distribution)
+    (Lines)
+    (Expires)
+    (Message-ID)
+    (References)
+    (User-Agent)))
+
+Otherwise `mail-header-format' will try to parse it differently, which we don't
+want."
   :group 'git-email
   :type '(string))