Adding comment styles for Rust (#29)

diff --git a/assets/languages.yaml b/assets/languages.yaml
index 505e95f..d501701 100644
--- a/assets/languages.yaml
+++ b/assets/languages.yaml
@@ -4971,6 +4971,7 @@
   codemirror_mode: rust
   codemirror_mime_type: text/x-rustsrc
   language_id: 327
+  comment_style_id: SlashAsterisk
 SAS:
   type: programming
   color: "#B34936"