removing small typo in lineagetree manager and adding the number_of_nodes property

src/LineageTree/lineageTree.py

@@ -355,6 +355,10 @@ def nodes(self) -> frozenset[int]:
         """Nodes of the tree"""
         return frozenset(self._successor.keys())
 
+    @dynamic_property
+    def number_of_nodes(self) -> int:
+        return len(self.nodes)
+
     @dynamic_property
     def depth(self) -> dict[int, int]:
         """The depth of each node in the tree."""

src/LineageTree/lineageTreeManager.py

@@ -430,6 +430,7 @@ def cross_lineage_edit_distance(
             The alignment between the nodes by the subtrees spawned by the nodes n1,n2 and the normalization function.`
         tuple(tree,tree), optional
             The two trees that have been mapped to each other.
+            Returned if `return_norms` is `True`
         """
 
         parameters = (