docs: add detailed docstrings to properties of Item

[Error44s]

Summary

This pull request enhances the Item class by adding detailed and professional docstrings for its properties and methods. The added docstrings improve clarity, maintainability, and usability for developers working with the PyCord library.

Information

• This PR fixes an issue.
• This PR adds something new (e.g. new method or parameters).
• This PR is a breaking change (e.g. methods or parameters removed/renamed).
• This PR is not a code change (e.g. documentation, README, typehinting, examples, ...).

Checklist

• I have searched the open pull requests for duplicates.
• If code changes were made, they have been tested.
  • I have updated the documentation to reflect the changes.
• If type: ignore comments were used, a comment is also left explaining why.
• I have updated the changelog to include these changes.

[Lulalaby]

merging for now, might be redundant next year tho