Merge bitcoindevkit/bdk#1325: Add `map_anchors` for `TxGraph`

5489f905a434ecc06867603c7c421e3e50d993ca feat(chain): add `map_anchors` for `TxGraph` and `ChangeSet` (Antonio Yang)
022d5a21cff6c46fb869f8fd538b4026e531ee57 test(chain) use `Anchor` generic on `init_graph` (Antonio Yang)

Pull request description:

  ### Description
  Fix #1295

  ### Checklists
  #### 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:
  evanlinjin:
    ACK 5489f905a434ecc06867603c7c421e3e50d993ca
  LLFourn:
    ACK 5489f905a434ecc06867603c7c421e3e50d993ca

Tree-SHA512: c8327f2e7035a46208eb32c6da1f9f0bc3e8625168450c5b0b39f695268e42b0b9053b6eb97805b116328195d77af7ca9edb1f12206c50513fbe295dded542e7

diff --cc crates/chain/src/tx_graph.rs
Simple merge

diff --cc crates/chain/tests/test_tx_graph.rs
Simple merge