Emitted JS / Gentype double-escapes output

[illusionalsagacity]

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When using the @as attribute with a value containing escape sequences (e.g., @as("with\"dquote")), the generated JavaScript incorrectly double-escapes the string. Additionally the parser can't handle exotic identifiers with a \".

I found this while looking at #8086 and removing String.escaped from this line:

rescript/compiler/gentype/TranslateTypeDeclarations.ml

Line 48 in 14721cb

| Some s -> s |> String.escaped

This existing test with an escaped double-quote \" in the @as annotation

rescript/tests/gentype_tests/typescript-react-example/src/Records.res

Lines 125 to 139 in 14721cb

	@genType
	type myRecBsAs = {
	@as("jsValid0")
	valid: string,
	@as("type")
	type_: string,
	@as("the-key")
	theKey: string,
	@as("with\"dquote")
	withDQuote: string,
	@as("with'squote")
	withSQuote: string,
	@as("1number")
	number1: string,
	}

Results it being double-escaped in the generated typescript types and javascript:

rescript/tests/gentype_tests/typescript-react-example/src/Records.gen.tsx

Lines 51 to 58 in 14721cb

	export type myRecBsAs = {
	readonly jsValid0: string;
	readonly type: string;
	readonly "the-key": string;
	readonly "with\\\"dquote": string;
	readonly "with'squote": string;
	readonly "1number": string
	};

rescript/tests/gentype_tests/typescript-react-example/src/Records.res.js

Lines 106 to 115 in 14721cb

	function testMyRecBsAs(x) {
	return [
	x.jsValid0,
	x.type,
	x["the-key"],
	x["with\\\"dquote"],
	x["with'squote"],
	x["1number"]
	];
	}

---

There's also a parser bug:

https://github.com/illusionalsagacity/rescript-compiler/blob/3293dcb812e416afccb0900df933bbbb533578f2/tests/gentype_tests/typescript-react-example/src/Records.res#L125-L142

Error in @tests/gentype-react-example:

  Syntax error!
  /rescript-compiler/tests/gentype_tests/typescript-react-example/src/Records.res:135:11-17

  133 ┆ @as("with\"dquote")
  134 ┆ withDQuote: string,
  135 ┆ \"with\"dquote2": string,
  136 ┆ @as("with'squote")
  137 ┆ withSQuote: string,

  Did you forget a `,` here?