Improve partial indenting performance

lib/handlebars/runtime.js

@@ -93,15 +93,8 @@ export function template(templateSpec, env) {
     }
     if (result != null) {
       if (options.indent) {
-        let lines = result.split('\n');
-        for (let i = 0, l = lines.length; i < l; i++) {
-          if (!lines[i] && i + 1 === l) {
-            break;
-          }
-
-          lines[i] = options.indent + lines[i];
-        }
-        result = lines.join('\n');
+        result =
+          options.indent + result.replace(/\n(?!$)/g, '\n' + options.indent);
       }
       return result;
     } else {