testuite: doctest: move to ghc recommended

Author: ulysses4ever

.github/workflows/quick-jobs.yml

@@ -69,8 +69,8 @@ jobs:
       - name: ghcup
         run: |
           ghcup config set cache true
-          ghcup install ghc 8.10.7
-          ghcup set ghc 8.10.7
+          ghcup install ghc recommended
+          ghcup set ghc recommended
       - name: Update Hackage index
         run: cabal v2-update
       - name: Install doctest

Makefile

@@ -74,7 +74,7 @@ ghcid-cli :
 # doctests (relies on .ghc.environment files)
 
 doctest :
-	doctest --fast Cabal-syntax/src Cabal/src
+	doctest --fast -XHaskell2010 Cabal-syntax/src Cabal/src
 
 # This is not run as part of validate.sh (we need hackage-security, which is tricky to get).
 doctest-cli :