message: Fix edge cases when inserting text in `Editor`
diff: @@ -17,8 +17,8 @@ impl<'a> Editor<'a> {
  pub fn insert(&mut self, character: char) {
  match self.cursor.selection() {
  Some((left, right)) => {
  - self.value.remove_many(left, right);
  self.cursor.move_left(&self.value);
  + self.value.remove_many(left, right);
  }
  _ => (),
  }
  @@ -32,8 +32,8 @@ impl<'a> Editor<'a> {
  match self.cursor.selection() {
  Some((left, right)) => {
  - self.value.remove_many(left, right);
  self.cursor.move_left(&self.value);
  + self.value.remove_many(left, right);
  }
  _ => (),
  }
  