Merge pull request #5741 from IntersectMBO/nm/plutus-preprocessor-nix-build-failure

Fix nix build failure in `plutus-preprocessor`

Author: lehins

cabal.project

@@ -70,7 +70,7 @@ program-options
   ghc-options: -Werror
 
 package plutus-preprocessor
-  haddock-options: "--optghc=-fplugin-opt PlutusTx.Plugin:defer-errors"
+  haddock-options: "--optghc=-fplugin-opt=PlutusTx.Plugin:defer-errors"
 
 package cardano-ledger-core
   flags: +asserts