docs: some observability doc tweaks (#14234)

* some tweaks

* reword

* spacing

* reads better

* add file name and change to .js to align with other docs

* nit

* Apply suggestion from @eltigerchino

* Apply suggestion from @eltigerchino

* Apply suggestion from @eltigerchino

* Apply suggestion from @eltigerchino

* Apply suggestion from @eltigerchino

Author: eltigerchino

documentation/docs/20-core-concepts/60-remote-functions.md

@@ -14,13 +14,16 @@ This feature is currently experimental, meaning it is likely to contain bugs and
 
 ```js
 /// file: svelte.config.js
-export default {
+/** @type {import('@sveltejs/kit').Config} */
+const config = {
 	kit: {
 		experimental: {
 			+++remoteFunctions: true+++
 		}
 	}
 };
+
+export default config;
 ```
 
 ## Overview

documentation/docs/30-advanced/68-observability.md

@@ -6,38 +6,39 @@ title: Observability
 	<p>Available since 2.29</p>
 </blockquote>
 
-> [!NOTE] This feature is experimental. Expect bugs and breaking changes in minor versions (though we'll do our best to keep those to an absolute minimum). Please provide feedback!
-
 Sometimes, you may need to observe how your application is behaving in order to improve performance or find the root cause of a pesky bug. To help with this, SvelteKit can emit server-side [OpenTelemetry](https://opentelemetry.io) spans for the following:
 
-- [`handle`](hooks#Server-hooks-handle) hook (`handle` functions running in a [`sequence`](@sveltejs-kit-hooks#sequence) will show up as children of each other and the root handle hook)
-- [`load`](load) functions (includes universal `load` functions when they're run on the server)
+- The [`handle`](hooks#Server-hooks-handle) hook and `handle` functions running in a [`sequence`](@sveltejs-kit-hooks#sequence) (these will show up as children of each other and the root `handle` hook)
+- Server [`load`](load) functions and universal `load` functions when they're run on the server
 - [Form actions](form-actions)
 - [Remote functions](remote-functions)
 
 Just telling SvelteKit to emit spans won't get you far, though — you need to actually collect them somewhere to be able to view them. SvelteKit provides `src/instrumentation.server.ts` as a place to write your tracing setup and instrumentation code. It's guaranteed to be run prior to your application code being imported, providing your deployment platform supports it and your adapter is aware of it.
 
-To enable both of these features, add the following to your `svelte.config.js`:
+Both of these features are currently experimental, meaning they are likely to contain bugs and are subject to change without notice. You must opt in by adding the `kit.experimental.tracing.server` and `kit.experimental.instrumentation.server` option in your `svelte.config.js`:
 
 ```js
 /// file: svelte.config.js
-export default {
+/** @type {import('@sveltejs/kit').Config} */
+const config = {
 	kit: {
-		+++experimental: {
-			tracing: {
+		experimental: {
+			+++tracing: {
 				server: true
 			},
 			instrumentation: {
 				server: true
-			}
-		}+++
+			}+++
+		}
 	}
 };
+
+export default config;
 ```
 
 > [!NOTE] Tracing — and more significantly, observability instrumentation — can have a nontrivial overhead. Before you go all-in on tracing, consider whether or not you really need it, or if it might be more appropriate to turn it on in development and preview environments only.
 
-## Agumenting SvelteKit's builtin tracing
+## Augmenting the built-in tracing
 
 SvelteKit provides access to the `root` span and the `current` span on the request event. The root span is the one associated with your root `handle` function, and the current span could be associated with `handle`, `load`, a form action, or a remote function, depending on the context. You can annotate these spans with any attributes you wish to record:
 
@@ -65,19 +66,20 @@ async function authenticate() {
 
 To view your first trace, you'll need to set up a local collector. We'll use [Jaeger](https://www.jaegertracing.io/docs/getting-started/) in this example, as they provide an easy-to-use quickstart command. Once your collector is running locally:
 
-- Turn on the experimental flag mentioned above in your `svelte.config.js` file
-- Use your package manager to install the dependencies you'll need
+- Turn on the experimental flags mentioned earlier in your `svelte.config.js` file
+- Use your package manager to install the dependencies you'll need:
   ```sh
   npm i @opentelemetry/sdk-node @opentelemetry/auto-instrumentations-node @opentelemetry/exporter-trace-oltp-proto import-in-the-middle
   ```
-- Create `src/instrumentation.server.ts` with the following:
+- Create `src/instrumentation.server.js` with the following:
 
-```ts
+```js
+/// file: src/instrumentation.server.js
 import { NodeSDK } from '@opentelemetry/sdk-node';
 import { getNodeAutoInstrumentations } from '@opentelemetry/auto-instrumentations-node';
 import { OTLPTraceExporter } from '@opentelemetry/exporter-trace-otlp-proto';
 import { createAddHookMessageChannel } from 'import-in-the-middle';
-import { register } from 'module';
+import { register } from 'node:module';
 
 const { registerOptions } = createAddHookMessageChannel();
 register('import-in-the-middle/hook.mjs', import.meta.url, registerOptions);
@@ -91,4 +93,4 @@ const sdk = new NodeSDK({
 sdk.start();
 ```
 
-Any server-side requests will now begin generating traces, which you can view in Jaeger's web console at [localhost:16686](http://localhost:16686).
+Now, server-side requests will begin generating traces, which you can view in Jaeger's web console at [localhost:16686](http://localhost:16686).