Add :def command to REPL for Juvix term definitions

[jonaprieto]

Introduce a new REPL command, :inspect, followed by a symbol name, allowing users to view and learn the actual Juvix term definition for the specified symbol, and possibly descovering nice treasures in the process. Feel free to suggest a better name for the command, perhaps :def, or :term.

A session might look like this:

Juvix REPL version 0.3.3
Stdlib.Prelude> 1
1
Stdlib.Prelude> :t 1
Nat
Stdlib.Prelude> :inspect Nat
builtin nat
type Nat :=
  | zero : Nat
  | suc : Nat → Nat;

Similarly as posted in:

• Implement :doc command in REPL for Judoc documentation access #2071

We might want to consider adding this as a helper subcommand.

• Name this :def

[jonaprieto]

Closed by

• Add :def command to the repl #2119