code: func (p *parser) consumeClosingParenthesis() bool {
  	i := p.i
  	p.skipWhitespace()
  	if p.i < len(p.s) && p.s[p.i] == ')' {
  		p.i++
  		return true
  	}
  	p.i = i
  	return false
  }
docs: // consumeClosingParenthesis consumes a closing parenthesis and any preceding
  // whitespace. It returns true if there was actually a parenthesis to skip.