docs: add links to read function (#13154)

closes #11871

Author: teemingc

documentation/docs/25-build-and-deploy/80-adapter-netlify.md

@@ -113,6 +113,6 @@ Additionally, you can add your own Netlify functions by creating a directory for
 
 You can't use `fs` in edge deployments.
 
-You _can_ use it in serverless deployments, but it won't work as expected, since files are not copied from your project into your deployment. Instead, use the `read` function from `$app/server` to access your files. `read` does not work inside edge deployments (this may change in future).
+You _can_ use it in serverless deployments, but it won't work as expected, since files are not copied from your project into your deployment. Instead, use the [`read`]($app-server#read) function from `$app/server` to access your files. `read` does not work inside edge deployments (this may change in future).
 
 Alternatively, you can [prerender](page-options#prerender) the routes in question.

documentation/docs/25-build-and-deploy/90-adapter-vercel.md

@@ -173,6 +173,6 @@ Projects created before a certain date may default to using an older Node versio
 
 You can't use `fs` in edge functions.
 
-You _can_ use it in serverless functions, but it won't work as expected, since files are not copied from your project into your deployment. Instead, use the `read` function from `$app/server` to access your files. `read` does not work inside routes deployed as edge functions (this may change in future).
+You _can_ use it in serverless functions, but it won't work as expected, since files are not copied from your project into your deployment. Instead, use the [`read`]($app-server#read) function from `$app/server` to access your files. `read` does not work inside routes deployed as edge functions (this may change in future).
 
 Alternatively, you can [prerender](page-options#prerender) the routes in question.

documentation/docs/30-advanced/50-server-only-modules.md

@@ -10,7 +10,7 @@ The [`$env/static/private`]($env-static-private) and [`$env/dynamic/private`]($e
 
 ## Server-only utilities
 
-The [`$app/server`]($app-server) module, which contains a `read` function for reading assets from the filesystem, can likewise only be imported by code that runs on the server.
+The [`$app/server`]($app-server) module, which contains a [`read`]($app-server#read) function for reading assets from the filesystem, can likewise only be imported by code that runs on the server.
 
 ## Your modules