Elixir 1.13 does not allow them in raw form anymore, resulting in errors like this when running the test:
== Compilation error in file test/pleroma/web/rich_media/parser_test.exs == ** (SyntaxError) test/pleroma/web/rich_media/parser_test.exs:136:45: invalid bidirectional formatting character in string: \u202C. If you want to use such character, use it in its escaped \u202C form instead