git-metadata: Add derivable traits

Add more derivable traits to structs in `radicle-git-metadata` types to
make them easier to use.

crates/radicle-git-metadata/src/commit.rs

@@ -11,7 +11,7 @@ use crate::author::Author;
 
 /// A git commit in its object description form, i.e. the output of
 /// `git cat-file` for a commit object.
-#[derive(Debug)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct CommitData<Tree, Parent> {
     tree: Tree,
     parents: Vec<Parent>,

crates/radicle-git-metadata/src/commit/headers.rs

@@ -7,7 +7,7 @@ const BEGIN_PGP: &str = "-----BEGIN PGP SIGNATURE-----\n";
 /// A collection of headers stored in [`super::CommitData`].
 ///
 /// Note: these do not include `tree`, `parent`, `author`, and `committer`.
-#[derive(Clone, Debug, Default)]
+#[derive(Clone, Debug, Default, PartialEq, Eq, Hash)]
 pub struct Headers(pub(super) Vec<(String, String)>);
 
 /// A `gpgsig` signature stored in [`super::CommitData`].

crates/radicle-git-metadata/src/commit/trailers.rs

@@ -85,13 +85,13 @@ impl<'a> Trailer<'a> {
 /// A version of the [`Trailer`] which owns its token and
 /// value. Useful for when you need to carry trailers around in a long
 /// lived data structure.
-#[derive(Debug)]
+#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub struct OwnedTrailer {
     pub token: OwnedToken,
     pub value: String,
 }
 
-#[derive(Debug)]
+#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub struct OwnedToken(String);
 
 impl Deref for OwnedToken {