ocp-indent-compat: Remove extra newline in empty comments (#2365)

CHANGES.md

@@ -30,7 +30,7 @@
 - Restore short form formatting of record field aliases (#2282, @gpetiot)
 - Tweaks the JaneStreet profile to be more consistent with ocp-indent (#2214, #2281, #2284, #2289, #2299, #2302, #2309, #2310, #2311, #2313, #2316, #2362, #2363, @gpetiot, @Julow)
 - Improve formatting of class signatures (#2301, @gpetiot, @Julow)
-- JaneStreet profile: treat comments as doc-comments (#2261, #2344, #2354, @gpetiot, @Julow)
+- JaneStreet profile: treat comments as doc-comments (#2261, #2344, #2354, #2365, @gpetiot, @Julow)
 - Don't indent attributes after a let/val/external (#2317, @Julow)
 - Adjust indentation of class-expr function body (#2328, @gpetiot)
 

lib/Cmts.ml

@@ -562,7 +562,7 @@ module Ocp_indent_compat = struct
     let pre, doc, post =
       let lines = String.split_lines txt in
       match lines with
-      | [] -> (false, txt, false)
+      | [] | [_] -> (false, txt, false)
       | h :: _ ->
           let pre = String.is_empty (String.strip h) in
           let doc = if pre then String.lstrip txt else txt in

test/passing/tests/js_source.ml

@@ -7951,3 +7951,5 @@ let _ =
     | Some _ -> foo
     | None -> baz)
 ;;
+
+(* *)

test/passing/tests/js_source.ml.ocp

@@ -10187,3 +10187,5 @@ let _ =
     | Some _ -> foo
     | None -> baz)
 ;;
+
+(* *)

test/passing/tests/js_source.ml.ref

@@ -10187,3 +10187,5 @@ let _ =
     | Some _ -> foo
     | None -> baz)
 ;;
+
+(* *)