Fix generic parameter defaults section in Generics.md - #2986

class Animal {
  name: string = "TS";
}

declare function create(): Container<HTMLDivElement, HTMLDivElement[]>;
declare function create<T extends HTMLElement>(element: T): Container<T, T[]>;
declare function create<T extends HTMLElement, U extends HTMLElement>(
  element: T,
  children: U[]
): Container<T, U[]>;

declare function create<T extends HTMLElement = HTMLDivElement, U = T[]>(
  element?: T,
  children?: U
): Container<T, U>;