#### Summary
This pull request adds detailed instructions for configuring ProtonMail's SMTP server in the `email-setup.md` documentation. The new section provides step-by-step guidance on generating SMTP tokens and configuring the `app.ini` file for ProtonMail.
#### Changes
- Added a new section under the "ProtonMail" heading in `email-setup.md`.
- Included instructions for generating SMTP tokens in ProtonMail settings.
- Provided an example configuration for the `app.ini` file to use ProtonMail's SMTP server.
Reviewed-on: https://gitea.com/gitea/docs/pulls/93
Reviewed-by: Lunny Xiao <xiaolunwen@gmail.com>
Reviewed-by: techknowlogick <techknowlogick@noreply.gitea.com>
Co-authored-by: talltechy <matt@mattwyen.me>
Co-committed-by: talltechy <matt@mattwyen.me>
- Always use a relative markdown link so that we can jump even if we edit it in local env or read it in code hosting server.
Reviewed-on: https://gitea.com/gitea/docs/pulls/1
