Style Guide: String coercion using string literal

[kitsonk]

Style Guide

Prior to ES6, the only clear way to coerce a string would be to use String(value), as value + '' coercions are unclear and arguably what is horribly wrong with JavaScript.

With the advent of string literals though, the construct of:

`${value}`

is clear in intent that whatever value is should be stringified into a string. It also performs significantly faster than String(value) in browsers that support it (though the downlevel emit from TypeScript is "" + value, which is still faster than String(value) though).

We should update the style guide to be explicit this is our preferred method for string coercion.