EIP-2737: Canonical format for referencing EIPs

Discussion thread for EIP-2737: Canonical EIP format.

TLDR: Always refer to EIPs via the hyphenated form EIP-X instead of EIPX.

This EIP is a duplicate of https://github.com/ethereum/EIPs/issues/1464.

Instead, I’ve opened a PR to update EIP-1 and the EIPs website: https://github.com/ethereum/EIPs/pull/2734