chore: minor improvement for docs

[ledigang]

Summary

Closes #_

• y/n | Does it introduce breaking changes?
• y/n | Is it dependent on a specific version of cargo-contract or pallet-revive?

minor improvement for docs

Description

Checklist before requesting a review

• I have added an entry to CHANGELOG.md
• I have commented on my code, particularly in hard-to-understand areas
• I have added tests that prove my fix is effective or that my feature works
• Any dependent changes have been merged and published in downstream modules

[Daanvdplas]

Thank you!

[ledigang]

Thank you!

@Daanvdplas My pleasure. If there's anything need I to do, please feel free to tell me.