Add reference for two optional chain SyntaxErrors

[Josh-Cena]

Part of mdn/mdn#505

[github-actions]

Preview URLs

• /en-US/docs/Web/JavaScript/Reference/Errors/Bad_new_optional
• /en-US/docs/Web/JavaScript/Reference/Errors/Bad_optional_template
• /en-US/docs/Web/JavaScript/Reference/Operators/Operator_precedence
• /en-US/docs/Web/JavaScript/Reference/Operators/Optional_chaining
• /en-US/docs/Web/JavaScript/Reference/Operators/new

External URLs (2)

URL: /en-US/docs/Web/JavaScript/Reference/Errors/Bad_new_optional
Title: SyntaxError: new keyword cannot be used with an optional chain

• Should “optional new” be implemented? tc39/proposal-optional-chaining#22 (1 time) (Note! This may be a new URL 👀)

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URL: /en-US/docs/Web/JavaScript/Reference/Errors/Bad_optional_template
Title: SyntaxError: tagged template cannot be used with optional chain

• tagged template literals should be allowed (for completeness) tc39/proposal-optional-chaining#54 (1 time) (Note! This may be a new URL 👀)

[sideshowbarker]

Suggested change

	Note that there's no needs to use `?.` on the `new` expression itself: `new a()?.b`, because `new` is guaranteed to produce a non-nullish object value.
	Note that there's no need to use `?.` on the `new` expression itself: `new a()?.b`, because `new` is guaranteed to produce a non-nullish object value.

[sideshowbarker]

whoops, sorry — fat-finger merged this before committing that typo fix