feat: JS expression handles

Expr::kind maps each of oxc's expressions to bun's ExprKind, with the
accessors that bun's printer calls: operators, members, calls, chains,
templates, regexes and JSX. The tables record the parentheses around
each node. oxc's n-ary sequence is one ExprKind::Sequence rather than
nested commas, and a JSX child in braces is the expression in them.