Improve functionality for adding comments

[lehins]

With huddle we lost the ability to have inline comments that are incredibly useful for documenting various fields.

Great example is thresholds: https://github.com/IntersectMBO/cardano-ledger/blob/e4af931415c9b6ba8657105ec61c083946ada453/eras/conway/impl/cddl-files/conway.cddl#L196-L205

We would like to be able to define with comments like so:

drep_voting_thresholds = [ unit_interval ; MotionNoConfidence
                         , unit_interval ; CommitteeNormal
                         , unit_interval ; CommitteeNoConfidence
                         , unit_interval ; UpdateToConstitution
                         , unit_interval ; HardForkInitiation
                         , unit_interval ; PPNetworkGroup
                         , unit_interval ; PPEconomicGroup
                         , unit_interval ; PPTechnicalGroup
                         , unit_interval ; PPGovGroup
                         , unit_interval ; TreasuryWithdrawal
                         ]

Same applies to maps, not just arrays:

protocol_param_update = { ? 0 : coin         ; minfeeA
                        , ? 1 : coin         ; minfeeB
                        , ? 2 : uint .size 4 ; max block body size
                        , ? 3 : uint .size 4 ; max transaction size
                        , ? 4 : uint .size 2 ; max block header size
                        , ...

Related ticket on the ledger repo: IntersectMBO/cardano-ledger#4522

[nc6]

Should already be addressed by 779885b