Merge bitcoindevkit#1930: feat(chain): Add method for constructing TxGraph from a ChangeSet

f68cfa8 feat(chain): Add method for constructing `TxGraph` from a `ChangeSet` (uvuvuwu)

Pull request description:

  ### Description
  * Added a `from_changeset()` function to `TxGraph` implementation
  * This function initializes a new `TxGraph` and applies the given `ChangeSet`
  * The method allows constructing a `TxGraph` directly from a `ChangeSet`,
    simplifying graph creation.

  #### 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
  * [x] I've added docs for the new feature

ACKs for top commit:
  evanlinjin:
    ACK f68cfa8
  LagginTimes:
    ACK f68cfa8
  AmosOO7:
    ACK bitcoindevkit@f68cfa8

Tree-SHA512: 9301bb606cf131e0a9871fad0cfa5b50ccce810717672a68bc5c256bb643b75fa04682b3c22510194c4e278aa56fe467eeeee343ade50c47bfa2713c41a64abf

Author: evanlinjin

crates/chain/src/tx_graph.rs

@@ -1216,6 +1216,13 @@ impl<A: Anchor> TxGraph<A> {
         self.try_list_expected_spk_txids(chain, chain_tip, indexer, spk_index_range)
             .map(|r| r.expect("infallible"))
     }
+
+    /// Construct a `TxGraph` from a `changeset`.
+    pub fn from_changeset(changeset: ChangeSet<A>) -> Self {
+        let mut graph = Self::default();
+        graph.apply_changeset(changeset);
+        graph
+    }
 }
 
 /// The [`ChangeSet`] represents changes to a [`TxGraph`].