Add link "Definitely Typed"

Author: alinnert

src/links.json

@@ -840,6 +840,13 @@
           "icon": "typescript",
           "color": "#007acc"
         },
+        {
+          "title": "DefinitelyTyped",
+          "url": "https://definitelytyped.org",
+          "description": "Type definitions for existing JS code.",
+          "searchUrl": "https://www.typescriptlang.org/dt/search?search={search}",
+          "searchConcat": "+"
+        },
         {
           "title": "JSDoc",
           "url": "https://jsdoc.app"