docs: Add relay host config guide for Gmail

[in-seo]

Description

deployed docs example

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I used Gmail as the relay host and succeeded after several attempts. Based on this experience, I would like to contribute to the docs on how to quickly connect to Gmail SMTP.
Currently, the part about integrating with the Gmail SMTP server cannot be found in the guide.
Therefore, I created guidelines such as how to use two-step authentication to use Gmail SMTP, what values ​​should be entered in the host and port, and how to change the sender address.

Here is the link if this docs will be deployed. Gmail SMTP

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Improvement (non-breaking change that does improve existing functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation (README.md or the documentation under docs/)
• If necessary, I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• I have added information about changes made in this PR to CHANGELOG.md

[casperklein]

IMO the term "Gmail SMTP" is a bit confusing. Why not something like "(Configuring) Gmail as relay host"?

PS: If you replace V with X in your post above, the boxes will be displayed with a nice check mark.

[polarathene]

Thanks for the contribution!

Most of this feedback I've provided suggestions you can apply via Github directly, then you can apply any additional changes manually 👍

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Guide for applying suggestions via Github web UI

If you're new to these reviews (I think you mentioned this is something you are getting experience at?), you can go into the "Files changed" tab here:

Then you will see each suggestion that has been provided by reviewers has a "Add suggestion to batch" button, click these if you agree and want to let Github apply the update:

Up top you'll get another button "Commit suggestions" that you can use once you've added all the suggestions you want to apply, it will let you enter a commit message and confirm to add all the suggestions you selected in a single commit:

[polarathene]

Ohhhh ok. So what is the value from the earlier Gmail Account ID link? (not accessible if you're not signed in)

You are definitely going for the personal Gmail here and this admonition is good to raise awareness that it should be an App Password, not the users personal credentials. I think that extra clarity should be added to the earlier example with link instead of "Gmail Account ID"?

[in-seo]

0. apply two ways (First, setup through Google Workspace and trusts via IP address, Second, regular credentials and there's 2FA) to configure for relay with gmail. Previously i suggested only one method!
1. change words 'Gmail SMTP' to 'Configure Gmail as a relay host'
2. removed tips that may not be helpful.

Thanks for @polarathene help.
If you have any further requests please comment me.

[github-actions]

Documentation preview for this PR is ready! 🎉

Built with commit: df82202

[polarathene]

Thank you for the quick response to feedback! 😎

I've manually applied some additional changes and will merge this now. Great first contribution thanks! ❤️