Equivalent to using mark() and restore_a_mark() from before, except it runs even if we return a SyntaxError. Also removes the deprecated reconsume_current_input_token() call - this never actually did anything useful anyway.
inherit()
UnresolvedSV::create()
<color-interpolation-method>
PercentageOr
@container
<ident>
<custom-ident>
@property/syntax
parse_syntax_component
<integer>
Parser