Update .ocamlformat config according to 0.14.2 release (#1018)

Author: gpetiot

.ocamlformat

@@ -6,8 +6,7 @@ parens-tuple=multi-line-only
 type-decl=sparse
 wrap-comments=false
 wrap-fun-args=false
-doc-comments-val=after
-doc-comments=after
+doc-comments=after-when-possible
 indicate-multiline-delimiters=no
 break-infix-before-func
 break-separators=before