Consider adding 's' and 'n' to serialized form for String and BigInt

[sffc]

Without looking at the larger string serialization problem (#116), I wanted to discuss whether the string form should differentiate between String, Number, and BigInt (and arrays thereof). Maybe BigInt could use n instead of e+0.

For example, currently we have: [1e0 ~]

How about:

• [1e0 ~] = new Amount(1e0, null)
• [1n ~] = new Amount(1n, null)
• [1e0s ~] = new Amount("1e0", null)

[eemeli]

What's the use case for .toString() including the value type in its output? I at least see it primarily meant as a tool for debugging and logging, which don't necessarily need to differentiate the value type.

[sffc]

toString is meant primarily for round-tripping.

If you are debugging, the type is also useful to know.

We should write down the use cases for toString because I'm still not 100% convinced we need it.