Fix HTML lang attribute (#169)

d-dandrew

22.27.2019 b53505820437ff778ab724d7f751ee003811ff7e

 CONTRIBUTORS.md

@@ -34,3 +34,4 @@
- [Paul Lettington](https://github.com/plett)
- [Thomas Vochten](https://github.com/thomasvochten)
- [Caspar Krieger](https://www.asparck.com)
- [D_DAndrew](https://d-dandrew.github.io)