Preserve newlines in messages.

lib/pleroma/web/twitter_api/twitter_api.ex

@@ -13,6 +13,7 @@ def create_status(user = %User{}, data = %{}) do
     context = ActivityPub.generate_context_id
 
     content = HtmlSanitizeEx.strip_tags(data["status"])
+    |> String.replace("\n", "<br>")
 
     mentions = parse_mentions(content)
 

test/web/twitter_api/twitter_api_test.exs

@@ -27,13 +27,13 @@ test "create a status" do
     object = Repo.insert!(%Object{data: object_data})
 
     input = %{
-      "status" => "Hello again, @shp.<script></script>",
+      "status" => "Hello again, @shp.<script></script>\nThis is on another line.",
       "media_ids" => [object.id]
     }
 
     { :ok, activity = %Activity{} } = TwitterAPI.create_status(user, input)
 
-    assert get_in(activity.data, ["object", "content"]) == "Hello again, <a href='shp'>@shp</a>."
+    assert get_in(activity.data, ["object", "content"]) == "Hello again, <a href='shp'>@shp</a>.<br>This is on another line."
     assert get_in(activity.data, ["object", "type"]) == "Note"
     assert get_in(activity.data, ["object", "actor"]) == user.ap_id
     assert get_in(activity.data, ["actor"]) == user.ap_id