Fix link (#1084)

Author: SleeplessByte

concepts/strings/about.md

@@ -31,7 +31,7 @@ You can find all the methods in the [MDN docs][mdn-docs].
 
 ## String interpolation
 
-Strings in JavaScript support concatenation using [`+` and slight variations][https://developer.mozilla.org/en-us/docs/web/javascript/reference/global_objects/string#long_literal_strings] and interpolation using [string template literals][mdn-template-strings].
+Strings in JavaScript support concatenation using [`+` and slight variations][mdn-concatenation] and interpolation using [string template literals][mdn-template-strings].
 
 ```javascript
 const NUMBER_OF_CATS = 4;