lib: fix various typos

This commit fixes typos unintentionally introduced in d9c68e0, when
renaming `jj branch` to `jj bookmark`.

lib/src/dag_walk.rs

@@ -277,7 +277,7 @@ impl<T: Ord, ID: Hash + Eq + Clone, E> TopoOrderReverseLazyInner<T, ID, E> {
     }
 }
 
-/// Splits DAG at single fork point, and extracts bookmarky part as sub graph.
+/// Splits DAG at single fork point, and extracts branchy part as sub graph.
 ///
 /// ```text
 ///  o | C
@@ -1067,7 +1067,7 @@ mod tests {
     }
 
     #[test]
-    fn test_topo_order_reverse_cycle_to_bookmarky_sub_graph() {
+    fn test_topo_order_reverse_cycle_to_branchy_sub_graph() {
         // This graph:
         //  o D
         //  |\

lib/tests/test_operations.rs

@@ -283,7 +283,7 @@ fn test_reparent_range_linear() {
 }
 
 #[test]
-fn test_reparent_range_bookmarky() {
+fn test_reparent_range_branchy() {
     let settings = testutils::user_settings();
     let test_repo = TestRepo::init();
     let repo_0 = test_repo.repo;
@@ -297,7 +297,7 @@ fn test_reparent_range_bookmarky() {
         parents.try_into().unwrap()
     }
 
-    // Set up bookmarky operation graph:
+    // Set up branchy operation graph:
     // G
     // |\
     // | F

lib/tests/test_rewrite.rs

@@ -264,7 +264,7 @@ fn test_rebase_descendants_backward() {
 }
 
 #[test]
-fn test_rebase_descendants_chain_becomes_bookmarky() {
+fn test_rebase_descendants_chain_becomes_branchy() {
     let settings = testutils::user_settings();
     let test_repo = TestRepo::init();
     let repo = &test_repo.repo;