use \() for escapes instead of $()

[WebFreak001]

Some languages like Swift add a new escape character (\() that marks the beginning of interpolation in interpolated strings.

I believe this makes more sense than $ as it is not inventing new syntax given the already existing language rules. This however means the short form for identifiers ($foo) won't work anymore.

example:

i"\(x) can be written as \(scientific)\(x) or \(fixed(20, 10))\(x)."