Add attribute-tools Community Extension to doc (#3229)

added attribute-tools Community Extension to doc

Author: jamcole

www/content/extensions/_index.md

@@ -31,6 +31,7 @@ htmx extensions are split into two categories:
 |--------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
 | [ajax-header](https://github.com/bigskysoftware/htmx-extensions/blob/main/src/ajax-header/README.md)                     | Adds an `X-Requested-With` header to all requests made by htmx                                                                                                                                                                                                                                |
 | [alpine-morph](https://github.com/bigskysoftware/htmx-extensions/blob/main/src/alpine-morph/README.md)                   | Alpine.js now has a lightweight [morph plugin](https://alpinejs.dev/plugins/morph) and this extension allows you to use it as the swapping mechanism in htmx which is necessary to retain Alpine state when you have entire Alpine components swapped by htmx.                                |
+| [attribute-tools](https://github.com/jamcole/htmx-ext-attribute-tools/blob/main/README.md)                               | The `attribute-tools` extension allows you to specify attributes that will be swapped onto or off of the elements by using an `attributes` or `data-attributes` attribute. (similar to class-tools)                                                                                                                             |
 | [class-tools](https://github.com/bigskysoftware/htmx-extensions/blob/main/src/class-tools/README.md)                     | The `class-tools` extension allows you to specify CSS classes that will be swapped onto or off of the elements by using a `classes` or `data-classes` attribute.                                                                                                                              |
 | [client-side-templates](https://github.com/bigskysoftware/htmx-extensions/blob/main/src/client-side-templates/README.md) | This extension supports transforming a JSON/XML request response into HTML via a client-side template before it is swapped into the DOM.                                                                                                                                                      |
 | [debug](https://github.com/bigskysoftware/htmx-extensions/blob/main/src/debug/README.md)                                 | This extension includes log all htmx events for the element it is on, either through the `console.debug` function or through the `console.log` function with a `DEBUG:` prefix.                                                                                                               |