Update readme.md

readme.md

@@ -73,7 +73,7 @@ This code needs the following libraries to be built:
 - [Lua][16]
 - [magicenum][10]
 - [RapidJson][1]
-- [SDL] [19] - Optional, only for building IM GUI apps (still in development)
+- [SDL][19] - Optional, only for building IM GUI apps (still in development)
 - [Sol][17]
 - [spdlog][4]
 - [sigslot][15]
@@ -102,4 +102,4 @@ All code is licensed under the [MPLv2 License][5].
 [17]: https://github.com/ThePhD/sol2
 [18]: https://github.com/google/cityhash
 [19]: https://github.com/libsdl-org/SDL
-[20]: https://github.com/ocornut/imgui
+[20]: https://github.com/ocornut/imgui