GHC proposal process is active at same time.
To avoid confusion about starting process, it's good that pre-starting process is written somewhere.
What about directly writing at README.rst as following?
(It's simpler than PR.)
[README.rst]
While the process is open for everyone to participate, contributing entirely
new issues is currently limited to the members of the Core Language Committee.
+ If you want to create entirely new issue, privately talk with member of the
+ committee or ask on haskell-prime mailing list.
I think that non-member will understand pre-process :)
Regards,
Takenobu