feat: improve real-time chart example; add small refinements to via core files

h/attributes.go

@@ -34,6 +34,10 @@ func Class(v string) H {
 	return gh.Class(v)
 }
 
+func Role(v string) H {
+	return gh.Role(v)
+}
+
 // Data attributes automatically have their name prefixed with "data-".
 func Data(name, v string) H {
 	return gh.Data(name, v)