update contributing docs (#9061)

Author: vivianyentran

docs/contributing/environment.mdx

@@ -26,7 +26,7 @@ make
 Now run the development webserver:
 
 ```bash
-yarn start
+yarn dev
 ```
 
 You will now be able to access docs via http://localhost:3000.

docs/contributing/linking.mdx

@@ -95,15 +95,13 @@ This type of link can be used also for linking to anchors on external pages:
 
 ## Images
 
-All images must live in the `/public/` folder in order to be processed correctly.
+All images live in the `/public/` folder. You can reference images in this folder by using its full path (minus `/public/`).
 
-The folder structure of `/docs/` is duplicated in `/public/` so that you can still use relative paths to reference images in your content files. For instance, files (such as `index.mdx`) in the `/docs/platforms/android/enriching-events/attachments/` folder can reference images (such as `attachments-access.png`) living in the `/public/platforms/android/enriching-events/attachments/` folder like this:
+For instance, to use the image, `/public/product/alerts/issue-alert.png`, in any file:
 
-`![Attachments Access](attachments-access.png)`
+`![Image alt text](product/alerts/issue-alert.png)`
 
-Content files that live elsewhere (such as `/docs/product/accounts/quotas/manage-attachments-quota.mdx`) can still use the same image by referencing it like so (`/public` does not need to be included in the path):
-
-`![Attachments Access](/platforms/android/enriching-events/attachments/attachments-acccess.png)`
+The folder structure of `docs` is duplicated in `public` so that you can still use relative paths to reference images in your content files. For more details, see [Images](/contributing/pages/images).
 
 ## Email address
 

docs/contributing/pages/images.mdx

@@ -0,0 +1,20 @@
+---
+title: Images
+noindex: true
+---
+
+All images must live in the [`public`](https://github.com/getsentry/sentry-docs/tree/master/public) folder in order to be processed correctly.
+
+The folder structure of `docs` is duplicated in `public` so that you can still use relative paths to reference images in your content files.
+
+For instance, the file, `docs/product/alerts/alert-types.mdx`, can reference the image, `public/product/alerts/issue-alert.png`, like so :
+
+```markdown {filename:docs/product/alerts/alert-types.mdx}
+![Issue alert](issue-alert.png)
+```
+
+Content files that live elsewhere (such as `/docs/platform/apple/index.mdx`) can still use the same image by referencing it with the full path (`/public` does not need to be included), like so:
+
+```markdown {filename:/docs/platform/apple/index.mdx}
+![Issue alert](/product/alerts/issue-alert.png)
+```

docs/contributing/pages/redirects.mdx

@@ -3,17 +3,31 @@ title: Redirects
 noindex: true
 ---
 
-Redirects are supported via yaml frontmatter in `.md` and `.mdx` files:
 
-```yaml
----
-redirect_from:
-  - /performance-monitoring/discover/
----
-```
+Redirects allow you to automatically redirect an incoming request path to a new destination path. When you move or rename a file, you should make sure to set up a redirect from the old path to the new path, so that the old URL still takes users to the right place.
+
+## Add a New Redirect
 
-These will be generated as both client-side (using an empty page with a meta tag) and server-side (nginx rules).
+Redirects are configured in [`next.config.js`](https://github.com/getsentry/sentry-docs/blob/master/next.config.js) and are checked before the filesystem (including pages and `/public` files ). The `redirects` function returns an array holding redirect objects.
 
-## Vercel
+To add a new redirect, add a new object in the redirects array with the following properties:
 
-Because docs.sentry.io is hosted on Vercel, there are also some wider-reaching redirects implemented to cover legacy URLs which cannot be re-implemented using `redirect_from`. See `vercel.json` for these.
+- `source`: The incoming request path pattern.
+- `destination`: The new destination path you want to route to instead.
+- `permanent`: Whether the redirect is permanent and should be cached forever (`true`) or is temporary (`false`).
+
+### Example Redirect
+
+The example below adds a redirect for the alerts page after its parent folder was renamed from `alerts-notifications` to `alerts`.
+
+```javascript {filename:next.config.js}
+redirects() {
+    return [
+      {
+        source: '/product/alerts-notifications/',
+        destination: '/product/alerts/',
+        permanent: true,
+      },
+    ]
+}
+```