Document the fluent email Rule validation

[SanderMuller]

Documentation for laravel/framework#54067

[DanielSpravtsev]

Would be great to see some use cases/examples for methods

[taylorotwell]

Yeah, explanation of what "strict" compliance means, or what spoofing means would be great! Please mark as ready for review when the requested changes have been made.

[shaedrich]

Yeah, explanation of what "strict" compliance means, or what spoofing means would be great! Please mark as ready for review when the requested changes have been made.

A good place might be here, where it's already mentioned:

docs/validation.md

Lines 1213 to 1224 in 8c527b5

	The example above will apply the `RFCValidation` and `DNSCheckValidation` validations. Here's a full list of validation styles you can apply:
	<div class="content-list" markdown="1">
	- `rfc`: `RFCValidation`
	- `strict`: `NoRFCWarningsValidation`
	- `dns`: `DNSCheckValidation`
	- `spoof`: `SpoofCheckValidation`
	- `filter`: `FilterEmailValidation`
	- `filter_unicode`: `FilterEmailValidation::unicode()`
	</div>

[shaedrich]

You might want to link this:

- The `filter` validator, which uses PHP's `filter_var` function, ships with Laravel and was Laravel's default email validation behavior prior to Laravel version 5.8.
+ The `filter` validator, which uses PHP's [`filter_var` function](https://www.php.net/manual/en/filter.constants.php#constant.filter-validate-email), ships with Laravel and was Laravel's default email validation behavior prior to Laravel version 5.8.
 
[!WARNING]

[shaedrich]

You could link this:

Suggested change

	> The `dns` and `spoof` validators require the PHP `intl` extension.
	> The `dns` and `spoof` validators require the [PHP `intl` extension](https://www.php.net/manual/de/book.intl.php).

[shaedrich]

Doesn't have #### Defining Default Email Rules an heading level too high? 🤔

[SanderMuller]

Would be great to see some use cases/examples for methods

@DanielSpravtsev I've been working on some improvements, could you have a look?