Parser now handles `SomeEnum::Variant` in match arm patterns, emitting
a Variant pattern node with enum_name and variant fields. Previously
these fell through to Binding, producing broken codegen.
JS codegen: emit str_eq check against the variant name string (El enums
are plain strings at runtime). C codegen: same, via EL_STR + str_eq.
Rebuild elc to pick up the parser change.
Will Anderson
0f1da43a97