beautify 1st part of the tutorial

1-js/4-data-structures/7-array/5-calculator-for-input/solution.md

@@ -4,20 +4,20 @@
 //+ run demo
 var numbers = [];
 
-while(true) {
+while (true) {
 
   var value = prompt("Введите число", 0);
-  
+
   if (value === "" || value === null || isNaN(value)) break;
 
   numbers.push(+value);
 }
 
 var sum = 0;
-for(var i=0; i<numbers.length; i++) {
+for (var i = 0; i < numbers.length; i++) {
   sum += numbers[i];
 }
 
-alert(sum);
+alert( sum );
 ```