Sometimes you want a function that returns a NodeSeq as a parameter,
but many times, you'll just want to pass a NodeSeq constant. In
those cases, this trait and it's implicit conversions come in really
handy. Basically, a NodeSeq constant or a NodeSeq function can be passed and
either will be implicitly converted into a NodeSeqFunc.
Sometimes you want a function that returns a NodeSeq as a parameter, but many times, you'll just want to pass a NodeSeq constant. In those cases, this trait and it's implicit conversions come in really handy. Basically, a NodeSeq constant or a NodeSeq function can be passed and either will be implicitly converted into a NodeSeqFunc.