Wrong precedence between as and &[mut]

[oxalica]

A common example:

fn main() {
    let a = 1;
    let _ = &a as *const _;
}

Will be parsed as:

<... omitted ...>
          REF_EXPR@[39; 53)
            AMP@[39; 40) "&"
            CAST_EXPR@[40; 53)
              PATH_EXPR@[40; 41)
                PATH@[40; 41)
                  PATH_SEGMENT@[40; 41)
                    NAME_REF@[40; 41)
                      IDENT@[40; 41) "a"
              WHITESPACE@[41; 42) " "
              AS_KW@[42; 44) "as"
              WHITESPACE@[44; 45) " "
              POINTER_TYPE@[45; 53)
                STAR@[45; 46) "*"
                CONST_KW@[46; 51) "const"
                WHITESPACE@[51; 52) " "
                PLACEHOLDER_TYPE@[52; 53)
                  UNDERSCORE@[52; 53) "_"
<... omitted ...>

The &[mut] operator should have higher precedence than as.

Related issue: #279 (closed)