Handle unicode escape sequence in template strings

[iBicha]

In js, you can do

console.log(`\u001b[31mHello`)

and it would print a red hello.

Brighterscript can parse \u escape sequence and replace it with the right Chr calls. E.g. \u001b[31mHello can be transpilied to Chr(27) + "[31mHello"

[TwitchBronBron]

I believe we already have something similar. There's a \c that directly corresponds with the char code.

https://github.com/rokucommunity/brighterscript/blob/master/docs/template-strings.md#escaping-unicode-characters

[iBicha]

I guess I missed that, thanks!