Locally enable ocamlformat

.github/workflows/main.yml

@@ -77,3 +77,9 @@ jobs:
           opam exec -- dune clean
           opam exec -- dune build
           git diff --exit-code
+
+      - name: Check that the changes are correctly formatted
+        if: matrix.os == 'ubuntu-latest'
+        run: |
+          opam install ocamlformat.0.24.1
+          opam exec -- dune build @fmt

.ocamlformat

@@ -0,0 +1,11 @@
+version=0.24.1
+disable=true
+
+break-cases=fit-or-vertical
+doc-comments=before
+cases-exp-indent=2
+dock-collection-brackets=false
+# Preserve begin/end
+exp-grouping=preserve
+module-item-spacing=preserve
+parse-docstrings=false

dune-project

@@ -3,5 +3,5 @@
 (using menhir 2.0)
 
 (cram enable)
-(formatting disabled)
+(formatting (enabled_for ocaml))
 (implicit_transitive_deps false)