nix: Fix haddock parse errors on GHC 8.10

Author: sgillespie

flake.nix

@@ -220,10 +220,12 @@
                   packages.cardano-ledger-conway.doHaddock = false;
                   packages.cardano-ledger-shelley.doHaddock = false;
                   packages.cardano-protocol-tpraos.doHaddock = false;
+                  packages.fs-api.doHaddock = false;
                   packages.ouroboros-network-framework.doHaddock = false;
                   packages.ouroboros-consensus-cardano.doHaddock = false;
                   packages.ouroboros-consensus.doHaddock = false;
                   packages.cardano-ledger-core.doHaddock = false;
+                  packages.plutus-ledger-api.doHaddock = false;
                   packages.wai-extra.doHaddock = false;
                 })