docs: Add documentation to a subset of available extensions (#24138)

I was able to use my experience with some of the Deno extensions to
flesh out their documentation a bit

I've provided docs for the following:
- web
- fetch
- net
- webidl
- url
- io
- crypto
- console

---------

Signed-off-by: Richard Carson <Rscarson@rogers.com>

1 files changed, 20 insertions, 2 deletions

diff --git a/ext/webidl/README.md b/ext/webidl/README.md
index cc4ccc6e9..0b52c6fbd 100644
--- a/ext/webidl/README.md
+++ b/ext/webidl/README.md
@@ -1,6 +1,24 @@
 # deno_webidl
 
-This crate implements WebIDL for Deno. It consists of infrastructure to do ECMA
--> WebIDL conversions.
+**This crate implements WebIDL for Deno. It consists of infrastructure to do
+ECMA -> WebIDL conversions.**
 
 Spec: https://webidl.spec.whatwg.org/
+
+## Usage Example
+
+From javascript, include the extension's source, and assign the following to the
+global scope:
+
+```javascript
+import * as webidl from "ext:deno_webidl/00_webidl.js";
+Object.defineProperty(globalThis, webidl.brand, {
+  value: webidl.brand,
+  enumerable: false,
+  configurable: true,
+  writable: true,
+});
+```
+
+Then from rust, provide `init_webidl::init_webidl::init_ops_and_esm()` in the
+`extensions` field of your `RuntimeOptions`