Add code highlighting where needed

Author: Alex Krawiec

docs/product/sentry-basics/distributed-tracing/generate-first-error.mdx

@@ -16,7 +16,7 @@ If you're using your own source code, skip this step. Instead, select your [plat
 
 1. In the `tracing-tutorial-frontend` repo, open `src/App.js` and update the `onClick` handler by replacing the string passed to the `getProduct()` function from `nonfat-water` to `debug-sentry`.
 
-```jsx {filename:App.js}
+```jsx {filename:App.js} {7}
     <div className="btn-parent">
         <button className="btn" onClick={() => getProduct("clown-shoes")}>
             Clown Shoes

docs/product/sentry-basics/distributed-tracing/initialize-sentry-sdk-backend.mdx

@@ -93,7 +93,7 @@ The configuration above enables Sentry's error monitoring feature, as well as it
 
 Be sure to import `instrument.js` at the top of your `server.js` file. Then import `Sentry` and set up the error handler after all controllers and before any other middleware:
 
- ``` javascript {filename:server.js}
+ ``` javascript {filename:server.js} {1-7, 26-36}
     // IMPORTANT: Make sure to import `instrument.js` at the top of your file.
     // If you're using ECMAScript Modules (ESM) syntax, use `import "./instrument.js";`
     require("./instrument.js");