Add ability to remove error listeners from parser

Author: surdus

src/parser.rs

@@ -53,6 +53,7 @@ pub trait Parser<'input>: Recognizer<'input> {
     fn add_error_listener(&mut self, listener: Box<dyn ErrorListener<'input, Self>>)
     where
         Self: Sized;
+    fn remove_error_listeners(&mut self);
     fn notify_error_listeners(
         &self,
         msg: String,
@@ -292,6 +293,8 @@ where
         self.error_listeners.borrow_mut().push(listener)
     }
 
+    fn remove_error_listeners(&mut self) { self.error_listeners.borrow_mut().clear(); }
+
     fn notify_error_listeners(
         &self,
         msg: String,