:host and ::slotted pseudo class/element functions are parsed incorrectly (used in shadow DOM)

[shagkur]

Following pseudo class function is parsed incorrectly:
:host(<simple_selector_sequence>)

Following pseudo element function is paresed incorrectly:
::slotted(<simple_selector_sequence>)

[shagkur]

Here's my PR (proposal)
#74

Unfortunately i was not able to add you as the reviewer to the PR

[phax]

Will be part of 6.4.1