site: Fix code editor text decoration style in Safari (#1531)

Author: askoufis

site/src/Code/ErrorHighlighter.css.ts

@@ -2,7 +2,7 @@ import { style } from '@vanilla-extract/css';
 import { vars } from '../themes.css';
 
 export const errorUnderline = style({
-  textDecoration: 'dashed',
+  textDecorationStyle: 'dashed',
   textDecorationColor: vars.palette.red,
   textDecorationThickness: '3px',
   textDecorationLine: 'underline',