lua lexer fix, don't require whitespace after function keyword
lua lexer fix, don't require whitespace after function keyword

spencerlyon2/pygments,spencerlyon2/pygments,spencerlyon2/pygments,spencerlyon2/pygments,spencerlyon2/pygments,spencerlyon2/pygments,spencerlyon2/pygments,spencerlyon2/pygments,spencerlyon2/pygments,spencerlyon2/pygments,spencerlyon2/pygments,spencerlyon2/pygments,spencerlyon2/pygments,spencerlyon2/pygments,spencerlyon2/pygments,spencerlyon2/pygments,spencerlyon2/pygments,spencerlyon2/pygments