Pretty-print well-known embedded term values as “literals”

[robrix]

This is only relevant once #174 is merged in.

For example, the embedding of the character 'h' is currently pretty-printed as 'h' : Character. It would be nice to instead pretty-print it as simply 'h'.

Likewise, instead of 'hello' : String, "hello" would suffice.

[robrix]

It would be great if we could generalize this s.t. we could pretty-print:

• Pair A B as (A, B)
• pair A B a b as (a, b)
• Pair A (Pair B C) as (A, B, C)
• pair A (Pair B C) a (pair B C b c) as (a, b, c)