Add JavaScript roadmap alert (#1615)

content/roadmaps/101-backend/content/103-learn-a-language/105-javascript.md

@@ -1,3 +1,9 @@
+<DedicatedRoadmap
+  href='/javascript'
+  title='JavaScript Roadmap'
+  description='Click to check the detailed JavaScript Roadmap.'
+/>
+
 # JavaScript
 
 JavaScript, often abbreviated JS, is a programming language that is one of the core technologies of the World Wide Web, alongside HTML and CSS. It lets us add interactivity to pages e.g. you might have seen sliders, alerts, click interactions, and popups etc on different websites -- all of that is built using JavaScript. Apart from being used in the browser, it is also used in other non-browser environments as well such as Node.js for writing server-side code in JavaScript, Electron for writing desktop applications, React Native for mobile applications and so on.