[css-cascade-5] Rename @layers to @layer

[fantasai]

The degenerate syntax for declaring a layer is @layer name;. We also have @layers name1, name2, name3; for doing multiple at once; I think it should just have the same at-keyword: @layer. No reason we can't, and it avoids confusing authors about the 's'.

[tabatkins]

Well, the degenerate syntax for a single layer is actually @layer foo {}.

But yeah, assuming there's no weird parsing quirks in impls with having an at-rule be ended either by a block or a semicolon, then I'm fine with this.

[css-meeting-bot]

The CSS Working Group just discussed [css-cascade-5] Rename @layers to@layer, and agreed to the following:

• RESOLVED: rename @layers to @layer

The full IRC log of that discussion

<dael> Topic: [css-cascade-5] Rename @layers to@layer
<dael> github: https://github.com//issues/5855
<dael> Rossen_: fantasai anything to add?
<dael> fantasai: Nope
<florian> Seems fine
<dael> Rossen_: Any feedback or objections to renaming @layers to @layer?
<miriam> I'm in favor
<Rossen_> q?
<leaverou> in favor
<dael> Rossen_: Hearing no objects and seeing IRC support
<dael> RESOLVED: rename @layers to @layer