Add docstrings to Wallet

[reez]

Description

The UDL file supports docstring comments.

Adds docstrings to Wallet

Supersedes #454

Notes to the reviewers

We can do a mega-PR, but this PR just takes a section of the UDL (separate PR's for each section).

Per 1.0.0 beta 5 https://docs.rs/bdk_wallet/latest/bdk_wallet/index.html

Notable, can be updated in this PR:

• Didn't include examples in code comments
• Didn't add code comments for constructors or persist or top-level Wallet

Follow up

• Add checklist item about adding docstrings (to PR template)
• Add section to README about docstrings (per Thunder)
• We probably want to standardize some minor formatting (that doesn't seem to effect output on Swift side though)
  • space/tabs/none
  • line breaks
  • alphabetize

Changelog notice

Checklists

All Submissions:

• I've signed all my commits
• I followed the contribution guidelines
• I ran cargo fmt and cargo clippy before committing

New Features:

• I've added tests for the new feature
• I've added docs for the new feature

Bugfixes:

• This pull request breaks the existing API
• I've added tests to reproduce the issue which are now passing
• I'm linking the issue being fixed by this PR

[thunderbiscuit]

This looks good! Might as well start merging that stuff. My only requested change would be to indent the comments to the same indentation level as the type/method they document, the way it's typically done in Rust/Python/Kotlin/Swift.

[reez]

This looks good! Might as well start merging that stuff. My only requested change would be to indent the comments to the same indentation level as the type/method they document, the way it's typically done in Rust/Python/Kotlin/Swift.

I can do that, sounds like a plan-

[reez]

This looks good! Might as well start merging that stuff. My only requested change would be to indent the comments to the same indentation level as the type/method they document, the way it's typically done in Rust/Python/Kotlin/Swift.

Done. rebased too. ready for merge after ACK

[reez]

This looks good! Might as well start merging that stuff. My only requested change would be to indent the comments to the same indentation level as the type/method they document, the way it's typically done in Rust/Python/Kotlin/Swift.

Done. rebased too. ready for merge after ACK

rebased again, ready for merge after ACK

[thunderbiscuit]

ACK 0329ddc.