update contributing docs

Author: ArnoStrouwen

docs/src/index.md

@@ -173,13 +173,16 @@ system:
 
   - Please refer to the
     [SciML ColPrac: Contributor's Guide on Collaborative Practices for Community Packages](https://github.com/SciML/ColPrac/blob/master/README.md)
-    for guidance on PRs, issues, and other matters relating to contributing to ModelingToolkit.
+    for guidance on PRs, issues, and other matters relating to contributing to SciML.
 
+  - See the [SciML Style Guide](https://github.com/SciML/SciMLStyle) for common coding practices and other style decisions.
   - There are a few community forums:
 
-      + The #diffeq-bridged channel in the [Julia Slack](https://julialang.org/slack/)
-      + [JuliaDiffEq](https://gitter.im/JuliaDiffEq/Lobby) on Gitter
-      + On the Julia Discourse forums (look for the [modelingtoolkit tag](https://discourse.julialang.org/tag/modelingtoolkit))
+      + The #diffeq-bridged and #sciml-bridged channels in the
+        [Julia Slack](https://julialang.org/slack/)
+      + The #diffeq-bridged and #sciml-bridged channels in the
+        [Julia Zulip](https://julialang.zulipchat.com/#narrow/stream/279055-sciml-bridged)
+      + On the [Julia Discourse forums](https://discourse.julialang.org)
       + See also [SciML Community page](https://sciml.ai/community/)
 
 ## Reproducibility