docs: update Smart_Contract_Signatures_Encoding.md

[mdqst]

To be more precise, replace "padded" with "zero-padded" to specify that the address is padded with zeros.

[huaweigu]

  with:
    header: Converntional Commits Error
    delete: false
    message: This repository uses conventional commits for versioning. Please ensure commits and PR title follow the specification.
  Refer to:
   [Conventional Commits Summary](https://www.conventionalcommits.org/en/v1.0.0/#summary)