Merge bitcoindevkit/bdk#1724: Type constraint on list canonical tx

2db98bad3962f8f2bb00719fbc9a50dbb9e913e8 fix(chain): type constraint on list canonical tx (Rob N)

Pull request description:

  Closes #1690

  #### All Submissions:

  * [x] I've signed all my commits
  * [x] I followed the [contribution guidelines](https://github.com/bitcoindevkit/bdk/blob/master/CONTRIBUTING.md)
  * [x] 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

ACKs for top commit:
  ValuedMammal:
    ACK 2db98bad3962f8f2bb00719fbc9a50dbb9e913e8

Tree-SHA512: 29a6b193dd1e9030541e389a6f4f3154edddf9cb2401c451468d6b0af8b2e00d807770cc8ec587f79f6cb1dabd87598dec9a1b3e63d0bda40ce75948805a3458