fix(website): make $ non-selectable

This will fix the copy button to copy the line without $.

Fixes #78

Change-Id: If569efb01e8bf0008d111bfcd74b5dbf3c73ea81
Signed-off-by: Paul Meyer <katexochen0@gmail.com>
Reviewed-on: https://cl.snix.dev/c/snix/+/30137
Reviewed-by: Florian Klink <flokli@flokli.de>
Tested-by: besadii

web/assets/scss/common/_custom.scss

@@ -1 +1,5 @@
 // Put your custom SCSS code here
+
+code.language-console .line .cl .gp {
+    user-select: none;
+}