fix: Escape reserved JSON characters before bundling into JS file

[kamilogorek]

Fixes denoland/deno#14012 and removes unnecessary line-ending from the processed output, as before the trimming, it always ended up looking like this:

__default = JSON.parse(`{"foo": "bar"}
`);

Escaping is done using https://docs.rs/escape8259/ and verified correctness with the https://www.rfc-editor.org/rfc/rfc8259 itself. I didn't see a point vendoring such a small library, but if necessary, we can do that.

[CLAassistant]

All committers have signed the CLA.

[kamilogorek]

cc @dsherret @bartlomieju

[kamilogorek]

Can I ask for actions reapproval?

[bartlomieju]

@kamilogorek done

[kamilogorek]

Uh, did deno lint and deno fmt but forgot that it also consists of rust code and didn't run rust fmt 🙄

[kamilogorek]

deno lint && deno fmt && deno test -A && cargo fmt && cargo test

Should be good now

[bartlomieju]

@kamilogorek Windows CI is still not happy

[kamilogorek]

Updated. I didnt pull EOL from deno_std/fs nor use isWindows from deno_std/_util/os as it's a simple oneliner, and for pulling whole dep for one tests sounds redundant.
We also need Raw.string anyway, so deno_std/fs/EOL couldn't be used directly.

[bartlomieju]

LGTM, thanks for looking into this Kamil!