Update docs for `git-email-headers`

There is now a `git-email-get-to-address-functions` variable that
determines the "to" address.

* git-email.el (git-email-headers): Refer to users to the relevant
  variable.

Signed-off-by: Xinglu Chen <public@yoctocell.xyz>

1 files changed, 2 insertions, 3 deletions

diff --git a/git-email.el b/git-email.el
index e399409..78db393 100644
--- a/git-email.el
+++ b/git-email.el
@@ -72,9 +72,8 @@
   '(subject from cc in-reply-to message-id references)
   "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."
+The 'to' address will always be inserted by calling
+`git-email-get-to-address-functions'."
   :type '(symbol)
   :group 'git-email
   :package-version '(git-email . "0.2.0"))