Update contribution guide to refer to the page in the wiki (#8447)

docs/CONTRIBUTING.md

@@ -1,14 +1,4 @@
-# Contribution Guide
+# DevilutionX Contribution Guide
+Welcome! Please review our [Contribution Guide](https://github.com/diasurgical/DevilutionX/wiki/Contributing) for more information!
 
-This guide outlines useful resources, tools and processes for contribution to
-DevilutionX.
-
-## C++ Standard
-
-Despite setting C++ standard to 20 in CMakeLists.txt, features from this version are not being used.
-The oldest compiler used is GCC 6.5 - and that defines our C++ feature set (meaning most of C++17).
-It's present only to take advantage of fmt::format build time errors.
-
-## Code style guide
-
-[The code style guide](https://github.com/diasurgical/devilutionX/wiki/Code-Style) is evolving with the project.
+_“A project is only as strong as its contributors. Thank you for helping us keep Diablo 1 alive and better than ever!”_