fix: don't use th in git rev parse -e unconditionally, use . instead. (#1023)

That way it shouldn't be grammatically incorrect.

Author: Byron

gitoxide-core/src/repository/revision/explain.rs

@@ -129,8 +129,8 @@ impl<'a> delegate::Navigate for Explain<'a> {
             self.out,
             "{}",
             match kind {
-                Traversal::NthAncestor(no) => format!("Traverse to the {no}th ancestor of revision named '{name}'"),
-                Traversal::NthParent(no) => format!("Select the {no}th parent of revision named '{name}'"),
+                Traversal::NthAncestor(no) => format!("Traverse to the {no}. ancestor of revision named '{name}'"),
+                Traversal::NthParent(no) => format!("Select the {no}. parent of revision named '{name}'"),
             }
         )
         .ok()