Generic/EmptyPHPStatement: add XML documentation

[rodrigoprimo]

Description

This PR adds documentation for the Generic/EmptyPHPStatement sniff.

I added one <standard> block per warning generated by this sniff. I considered adding another <standard> block to the beginning of the file summarizing what this sniff does. Something like:

<documentation title="Empty PHP Statement">
    <standard>
    <![CDATA[
    Empty PHP tags and superfluous semi-colons are not allowed.
    ]]>
    </standard>
    (...)
</documentation>

It does duplicate the content of the other <standard> blocks, but it provides a nice summary at the top of the documentation. Without the summary, there is a chance that someone skimming through the documentation might assume that this sniff is only about empty PHP tags and doesn't cover superfluous semi-colons.

I ended up not including the "summary" <standard> most of the other sniffs that contain multiple <standard> blocks don't contain a summary at the top. The only exception that I found is ArrayDeclarationStandard.xml. Any thoughts on this?

Suggested changelog entry

Add documentation for the Generic.CodeAnalysis.EmptyPHPStatement sniff

Related issues/external references

Part of #148

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
  • This change is only breaking for integrators, not for external standards or end-users.
• Documentation improvement

PR checklist

• I have checked there is no other PR open for the same change.
• I have read the Contribution Guidelines.
• I grant the project the right to include and distribute the code under the BSD-3-Clause license (and I have the right to grant these rights).
• I have added tests to cover my changes.
• I have verified that the code complies with the projects coding standards.
• [Required for new sniffs] I have added XML documentation for the sniff.

[rodrigoprimo]

One of the GitHub actions failed when trying to download PHPCS phar and it seems I don't have permission to run it again: https://github.com/PHPCSStandards/PHP_CodeSniffer/actions/runs/7275269656/job/19822876012?pr=166. I imagine it was due to a temporary problem that is not related to the changes in this PR.

[jrfnl]

One of the GitHub actions failed when trying to download PHPCS phar

This is a known issue and shouldn't happen anymore (for now) - see #204

[jrfnl]

Thanks for this PR @rodrigoprimo .

I considered adding another <standard> block to the beginning of the file summarizing what this sniff does.
...
It does duplicate the content of the other <standard> blocks, but it provides a nice summary at the top of the documentation.
...
Any thoughts on this?

I'm not against adding a summary block at the start when it has value, but I don't see it having value when it just repeats what's already in the other blocks.

So:
❌ Empty PHP tags and superfluous semi-colons are not allowed.
✔️ Empty PHP statements are not allowed (=> the empty PHP tag sets and superfluous semi-colons are symptoms, empty PHP statements is the actual problem the sniff addresses.)

[rodrigoprimo]

I'm not against adding a summary block at the start when it has value, but I don't see it having value when it just repeats what's already in the other blocks.

So:
❌ Empty PHP tags and superfluous semi-colons are not allowed.
✔️ Empty PHP statements are not allowed (=> the empty PHP tag sets and superfluous semi-colons are symptoms, empty PHP > statements is the actual problem the sniff addresses.)

Thanks for your input. In the end, I decided not to include a summary description at the top. I'm not super sure about and after trying it now it felt a little bit weird and repetitive since there is no clear separation between summary description and the description for the first <code_comparison> block.

This PR is ready for a final review.

[jrfnl]

LGTM! Thanks @rodrigoprimo !