[webcomponents] [Shadow] createShadowRoot() in spec example should be updated to have parameter (#106)

In spec EXAMPLE 5 and EXAMPLE 6, createShadowRoot() is called without ShadowRootInit
parameter. `{ mode: "open" }` should be supplied to them.

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Reply to this email directly or view it on GitHub:
https://github.com/w3c/webcomponents/issues/106