Add lambda type info

[janmasrovira]

This pr adds the _lambdaType :: Maybe Expression to Internal.Lambda.
This field will be Nothing before typechecking and Just _ after it.

The type is printed if present. For example if the input of juvix dev internal typecheck M.juvix --print-result is the following:

id : {A : Type} → A → A
id := λ { a := a}

Then the output is as follows:

id : {A : Type} → A → A
id {_ω209} := λ : _ω209 → _ω209 {| a := a}