pref: enable CSS grid

modules/libpref/init/all.js

@@ -2572,6 +2572,9 @@ pref("layout.css.variables.enabled", true);
 // Is support for CSS overflow-clip-box enabled for non-UA sheets?
 pref("layout.css.overflow-clip-box.enabled", false);
 
+// Is support for CSS grid enabled?
+pref("layout.css.grid.enabled", false);
+
 // Is support for CSS "grid-template-{columns,rows}: subgrid X" enabled?
 pref("layout.css.grid-template-subgrid-value.enabled", false);