fix: Add admonition CSS file to site.css (#54)

* Add admonition CSS file to site.css

* *Sigh*

Author: Techassi

src/css/site.css

@@ -17,4 +17,5 @@
 @import "highlight.css";
 @import "print.css";
 @import "landing.css";
+@import "admonition.css";
 @import "vendor/fontawesome.css";