Unknown pseudo class is tokenized wrong

[dummdidumm]

Please select any editor that you're experiencing this issue in.

• Visual Studio Code
• Sublime Text 2/3
• TextMate 2

Please provide the name/repo of the color scheme package you're using:

• irrelevant

(optional) Please include any packages/extensions you're using which could be conflicting:

• Deferring to the VS Code less syntax highlighting from within a Svelte file's style tag

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When using an unknown pseudo class, the highlighting ends up in a broken state, which can influence/mess up how the code after it is highlighted.

Example:

:global(.demo) {
    color: blue;
}

Will provide just meta.selector.less as the token for :global, but it should be entity.other.attribute-name.pseudo-class.less like it is for known pseudo classes, like is:(.demo) { }.

This came up in sveltejs/language-tools#2650, the repo for the Svelte extension which defers the syntax highlighting of <style lang="less"> to VS Code's built-in grammar, which to my knowledge is this grammar. :global is not a spec-ed pseudo class, rather a Svelte-specific one.

As far as I can see this is due to https://github.com/radium-v/Better-Less/blob/master/Syntaxes/Better%20Less.YAML-tmLanguage#L1952 only matching on a known list of pseudo classes.