disallow juxtaposition with literals ending in .

[JeffBezanson]

This is likely the less-breaking part of #15731.

[vtjnash]

@Keno how will the affect JuliaParser?

[Keno]

We'll have to make the corresponding change there.

[PallHaraldsson]

I was going to fix this, but can't tell why the link is missing in NEWS.. No big deal, but since the syntax seems identical, I'm puzzled..

[tkelman]

Someone will have to run the news-update script in contrib to add the actual link at the bottom of the file, I think.

[JeffBezanson]

I've just been assuming we'll run news-update before release --- trying to avoid merge conflicts at the end of the file.

[tkelman]

Yes that one is more reliably automatic and not a big deal to run long after the fact, as opposed to genstdlib which is better to run simultaneously.

[stevengj]

I grepped for things that this would break in Julia packages, and all I found was 1.im and 0.im in QuantumOptics.jl (cc @bastikr). I probably missed some, but it doesn't seem like this will break a lot of code.