pass URL-encoded form data

[izarma]

added a function form_encoded to pass URL-encoded form data in the request body.
wanted to discuss if the headers i'm adding by default are fine?

[foxzool]

Thanks for the contribution! Adding form_encoded support makes sense for the crate.

However, there are a few issues that need to be addressed before this can be merged:

1. Branch issue
This PR is opened from your master branch, which prevents CI from running and makes it hard to review incrementally. Please open a new PR from a feature branch (e.g. feat/form-encoded).

2. Default Accept: application/json header
You already flagged this yourself in the PR description — and I agree it shouldn't be the default here. URL-encoded form POSTs (OAuth token endpoints, HTML form submissions, etc.) commonly expect text/html, application/x-www-form-urlencoded, or nothing at all in the Accept header. Hardcoding application/json assumes too much about the server's response format. I'd suggest dropping the Accept header entirely from form_encoded() and letting the caller add it via .headers() if they need it.

3. Trailing whitespace cleanup
The unrelated trailing whitespace change on the EmptyArray doc comment line should be a separate PR (or we can just batch-fix formatting separately). Keeping unrelated changes out of feature PRs makes history cleaner.

Next steps:

• Close this PR
• Open a new one from feat/form-encoded
• Drop the Accept header from form_encoded()
• Keep the whitespace change out of the diff

Happy to re-review once it's on a feature branch. Thanks again!

[izarma]

Thank you for the review and sorry you had to merge this as is.