Improve indent in README.md

Co-authored-by: Jules Aguillon <[email protected]>

Author: Leonidas-from-XIV

README.md

@@ -47,8 +47,8 @@ for this is is slightly different to match the conventions of OCaml
 documentation comments:
 
     (** This is an documentation comment with an ocaml block
-    {@ocaml LABELS [
-    ]}
+        {@ocaml LABELS [
+        ]}
     *)