Add a test reproducing the issue #1983.

Author: Tim-ats-d

tests/test-dirs/document/issue1983.t

@@ -0,0 +1,107 @@
+The "document" command sometimes concatenates documentation for consecutive entries of variants or records.
+
+  $ document_pos () {
+  >   pos="$1"
+  >   ocamlmerlin single document -position "$pos" < test.ml | jq .value -r
+  > }
+
+  $ cat > test.ml <<EOF
+  > type variant =
+  >   | A (** A *)
+  >   | B (** B *)
+  >   | C (** C *)
+  > 
+  > type record =
+  >   { e : int (** e *)
+  >   ; f : int (** f *)
+  >   ; g : int (** g *)
+  >   }
+  > 
+  > let _ = A, B, C
+  > let _f x = x.e, x.f, x.g
+  > EOF
+
+Get doc for A
+FIXME: this should just be "A"
+  $ document_pos 12:9
+  A
+  B
+
+Get doc for B
+FIXME: this should just be "B"
+  $ document_pos 12:12
+  B
+  C
+
+Get doc for C
+  $ document_pos 12:15
+  C
+
+Get doc for e
+FIXME: this should just be "e"
+  $ document_pos 13:14
+  e
+  f
+
+Get doc for f
+FIXME: this should just be "f"
+  $ document_pos 13:19
+  e
+  f
+  g
+
+Get doc for g
+FIXME: this should just be "g"
+  $ document_pos 13:24
+  f
+  g
+
+  $ cat > test.ml <<EOF
+  > type variant =
+  >   | A
+  >   (** A *)
+  >   | B
+  >   (** B *)
+  >   | C
+  >   (** C *)
+  > 
+  > type record =
+  >   { e : int
+  >     (** e *)
+  >   ; f : int
+  >     (** f *)
+  >   ; g : int
+  >     (** g *)
+  >   }
+  > 
+  > let _ = A, B, C
+  > let _f x = x.e, x.f, x.g
+  > EOF
+
+Get doc for A
+  $ document_pos 18:9
+  A
+
+Get doc for B
+  $ document_pos 18:12
+  B
+
+Get doc for C
+  $ document_pos 18:15
+  C
+
+Get doc for e
+  $ document_pos 19:14
+  e
+
+Get doc for f
+FIXME: this should just be "f"
+  $ document_pos 19:19
+  e
+  f
+
+Get doc for g
+FIXME: this should just be "g"
+  $ document_pos 19:24
+  f
+  g