Merge bitcoindevkit/bdk#522: Add API for internal addresses

022256c91ac7a4d9324a1a7925394a948feec808 Fix comment on peek_address (Lloyd Fournier)
00f0901bac805360695d0c492df8fa809918863e Add API for internal addresses (LLFourn)

Pull request description:

  There are good reasons for applications to need to get internal
  addresses too. For example creating a transactions that splits an output
  into several smaller ones.

  ### 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:

  * [x] I've added tests for the new feature
  * [x] I've added docs for the new feature
  * [x] I've updated `CHANGELOG.md`

ACKs for top commit:
  notmandatory:
    ACK 022256c91ac7a4d9324a1a7925394a948feec808

Tree-SHA512: 0ead6669c9974332708ae6cba1a5be69cd4b3b6c7a21896efdce178d4406265ba072e1cf02d1913178d0a551f3b276d99b75676c632833964f87484e262a61b1

diff --cc CHANGELOG.md
index 17bf1624261f4577b3f7c95d6d758be614804787,ff48d6f56e898b3186e1d855a53e4132d2f87317..0c9f8927fed9221e718b75c07183106f4b6269da
--- 1/CHANGELOG.md
--- 2/CHANGELOG.md
+++ b/CHANGELOG.md
@@@ -6,13 -6,11 +6,14 @@@ and this project adheres to [Semantic V
  
  ## [Unreleased]
  
 -- Pin tokio dependency version to ~1.14 to prevent errors due to their new MSRV 1.49.0
  - Removed default verification from `wallet::sync`. sync-time verification is added in `script_sync` and is activated by `verify` feature flag.
  - `verify` flag removed from `TransactionDetails`.
+ - Add `get_internal_address` to allow you to get internal addresses just as you get external addresses.
  
 +## [v0.16.1] - [v0.16.0]
 +
 +- Pin tokio dependency version to ~1.14 to prevent errors due to their new MSRV 1.49.0
 +
  ## [v0.16.0] - [v0.15.0]
  
  - Disable `reqwest` default features.