Reduce string concatenations

Author: twharmon

frameworks/keyed/rendrjs/package-lock.json

@@ -10,7 +10,7 @@
     "webpack-cli": "5.1.4"
   },
   "dependencies": {
-    "@rendrjs/core": "0.1.234"
+    "@rendrjs/core": "0.1.236"
   },
   "js-framework-benchmark": {
     "frameworkVersionFromPackage": "@rendrjs/core",

frameworks/keyed/rendrjs/package.json

@@ -1,9 +1,10 @@
 import { button, div } from '@rendrjs/core';
 import { colSm6 } from './classes';
 
+let className = colSm6 + ' smallpad';
 export let Button = (props) => {
   return div({
-    class: `${colSm6} smallpad`,
+    class: className,
     slot: button({
       id: props.id,
       onclick: props.cb,