[libgpiod][PATCH] README: provide more info in Contributing

[Kent Gibson <warthog618@xxxxxxxxx>]

Add more detail to Contributing to make it easier for new users to
contribute.

Signed-off-by: Kent Gibson <warthog618@xxxxxxxxx>
---
I was tempted to add something on formatting with clang-format, but I'm
not 100% clear on the formatting policy myself.
Would be nice for that to be clarified.

 README | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/README b/README
index b71739e..8e726fe 100644
--- a/README
+++ b/README
@@ -275,8 +275,16 @@ were selected and help2man is available in the system.
 CONTRIBUTING
 ------------
 
-Contributions are welcome - please send patches and bug reports to
-linux-gpio@xxxxxxxxxxxxxxx (add the [libgpiod] prefix to the e-mail subject
-line) and stick to the linux kernel coding style when submitting new code.
+Contributions are welcome - please send questions, patches and bug reports
+to linux-gpio@xxxxxxxxxxxxxxx (add the [libgpiod] prefix to the e-mail
+subject line).  Note that the mailing list quietly drops HTML formatted
+e-mail, so be sure to send plain text[2].
+
+Code submissions should stick to the linux kernel coding style[3] and
+follow the kernel patch submission process[4] as applied to the libgpiod
+source tree.
 
 [1] https://github.com/bats-core/bats-core
+[2] https://docs.kernel.org/process/email-clients.html
+[3] https://docs.kernel.org/process/coding-style.html
+[4] https://docs.kernel.org/process/submitting-patches.html
-- 
2.40.1