message: Rename try to attempt as try is becoming a keyword in rust
diff: @@ -52,7 +52,7 @@ parser! {
  field_name: None,
  phrase,
  });
  - try(term_query)
  + attempt(term_query)
  .or(term_default_field)
  .map(UserInputLeaf::from)
  }
  @@ -83,12 +83,12 @@ parser! {
  let lower_bound = {
  let excl = (char('{'), term_val()).map(|(_, w)| UserInputBound::Exclusive(w));
  let incl = (char('['), term_val()).map(|(_, w)| UserInputBound::Inclusive(w));
  - try(excl).or(incl)
  + attempt(excl).or(incl)
  };
  let upper_bound = {
  let excl = (term_val(), char('}')).map(|(w, _)| UserInputBound::Exclusive(w));
  let incl = (term_val(), char(']')).map(|(w, _)| UserInputBound::Inclusive(w));
  - try(excl).or(incl)
  + attempt(excl).or(incl)
  };
  (
  optional((field(), char(':')).map(|x| x.0)),
  @@ -112,11 +112,11 @@ parser! {
  .or((char('+'), leaf()).map(|(_, expr)| expr.unary(Occur::Must) ))
  .or((char('('), parse_to_ast(), char(')')).map(|(_, expr, _)| expr))
  .or(char('*').map(|_| UserInputAST::from(UserInputLeaf::All) ))
  - .or(try(
  + .or(attempt(
  (string("NOT"), spaces1(), leaf()).map(|(_, _, expr)| expr.unary(Occur::MustNot))
  )
  )
  - .or(try(
  + .or(attempt(
  range().map(UserInputAST::from)
  )
  )
  @@ -160,7 +160,7 @@ parser! {
  where [I: Stream<Item = char>]
  {
  (
  - try(
  + attempt(
  chainl1(
  leaf().map(Element::SingleEl),
  binary_operand().map(|op: BinaryOperand|
  