Merge #3549

3549: Fix haddock error r=Jasagredo a=Jasagredo

This produces an error when building `cardano-node`.
```src/Ouroboros/Consensus/Storage/LedgerDB/InMemory.hs:470:9: error:
    parse error on input ‘-- ^ no blocks to apply to ledger state, return current LedgerDB’
    |
470 |         -- ^ no blocks to apply to ledger state, return current LedgerDB
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
```

Co-authored-by: Javier Sagredo <[email protected]>

Author: iohk-bors[bot]