Allow `hx-include` and `hx-vals` to specify an HTTP method explicitly

**Description:**

Currently, `hx-include` and `hx-vals` always include data in the same HTTP method as the primary request (`hx-get`, `hx-post`, etc.). However, there are cases where developers may need to include specific data as query parameters while making a `POST` request, or vice versa. This lack of flexibility often requires workarounds such as manually constructing URLs or modifying requests with JavaScript.

### Feature Request

Introduce a way to specify the HTTP method explicitly for `hx-include` and `hx-vals`. This would allow certain values to be included in the query string (`GET`) while keeping others in the request body (`POST`).

#### Proposed Syntax:

1. **Explicit HTTP method modifier**
- `hx-include="#filters get"` → Includes `#filters` fields as query parameters.
- `hx-include="#extra post"` → Ensures `#extra` fields are included in the request body.
- `hx-vals="{ key: 'value' } get"` → Appends `key=value` as a query parameter.
- `hx-vals="{ extra: '123' } post"` → Sends `extra=123` in the request body.

### Expected Behavior

With `hx-include="#filters get"` and `hx-vals="{ key: 'value' } get"`, an `hx-post` request would be transformed into:

```
POST /update?search=abc&category=1&key=value
Content-Type: application/x-www-form-urlencoded

name=John
```

### Use Case

A common scenario where this is useful is when updating a table’s data while maintaining filter parameters in the URL. For example:

```html

Submit

```

Here, `name=John` is sent in the request body, while `search=abc`, `category=1`, and `key=value` are included in the query string. This makes it possible to refresh the table with updated data while preserving filter state without requiring JavaScript workarounds.