error[preamble-requires-ref-description]: proposals mentioned in preamble header `description` must appear in `requires`
 --> input.md:4:40
  |
4 | description: This proposal is a sample EIP-9 and EIP-20 extension.
  |                                        ^^^^^ mentioned here
  |
error[preamble-requires-ref-title]: proposals mentioned in preamble header `title` must appear in `requires`
 --> input.md:3:31
  |
3 | title: A sample extension for EIP-1 and EIP-5
  |                               ^^^^^ mentioned here
  |                                         ^^^^^ mentioned here
  |