Update article.md

Fix some quotes for consistency with above paragraphs

Author: Heikrana

1-js/02-first-steps/08-operators/article.md

@@ -109,7 +109,7 @@ Here, operators work one after another. The first `+` sums two numbers, so it re
 ```js run
 alert('1' + 2 + 2); // "122" and not "14"
 ```
-Here, the first operand is a string, the compiler treats the other two operands as strings too. The `2` gets concatenated to `'1'`, so it's like `'1' + 2 = '12'` and `'12' + 2 = '122'`.
+Here, the first operand is a string, the compiler treats the other two operands as strings too. The `2` gets concatenated to `'1'`, so it's like `'1' + 2 = "12"` and `"12" + 2 = "122"`.
 
 The binary `+` is the only operator that supports strings in such a way. Other arithmetic operators work only with numbers and always convert their operands to numbers.