== should format ==
type T = {
    p1   : string;
    readonly  p2  :  number;
    [  p3 ]: number;
    "p4": string;
    [p5] ?  : number;
};

[expect]
type T = {
    p1: string;
    readonly p2: number;
    [p3]: number;
    "p4": string;
    [p5]?: number;
};
