List states

src/states.rs

@@ -238,6 +238,11 @@ impl States {
         self
     }
 
+    /// lists available states
+    pub fn states(&self) -> impl Iterator<Item = &str> {
+        self.states.keys().map(|s| s.as_str())
+    }
+
     /// Adds a single state
     pub fn add_state<'a>(
         &mut self,