feat: impl Default for Bookmark (#486)

Author: molpopgen

examples/haploid_wright_fisher.rs

@@ -64,7 +64,7 @@ fn simulate(
     let parent_picker = rand::distributions::Uniform::new(0, popsize);
     let breakpoint_generator = rand::distributions::Uniform::new(0.0, 1.0);
     let mut rng = rand::rngs::StdRng::seed_from_u64(seed);
-    let mut bookmark = tskit::types::Bookmark::new();
+    let mut bookmark = tskit::types::Bookmark::default();
 
     for birth_time in (0..num_generations).rev() {
         for c in children.iter_mut() {

src/types.rs

@@ -68,6 +68,12 @@ impl Bookmark {
     bookmark_setter!(set_provenances, provenances);
 }
 
+impl Default for Bookmark {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 #[cfg(test)]
 mod test {
 
@@ -82,7 +88,7 @@ mod test {
 
     #[test]
     fn test_bookmark_mutability() {
-        let mut b = Bookmark::new();
+        let mut b = Bookmark::default();
         assert_eq!(b.offsets.nodes, 0);
         assert_eq!(b.offsets.edges, 0);
         assert_eq!(b.offsets.individuals, 0);