Added escaping in line with VIP Coding Standards

[rebeccahum]

For more information, see: https://vip.wordpress.com/documentation/vip-go/code-review-blockers-warnings-notices/#validation-sanitization-and-escaping

Summary

This PR can be summarized in the following changelog entry:

• Added late escaping to output.

Relevant technical choices

For more information, see: https://vip.wordpress.com/documentation/vip-go/code-review-blockers-warnings-notices/#validation-sanitization-and-escaping

Checklist:

• [x] My code is tested.
• [x] My code is backward-compatible with WordPress 4.7 and PHP 7.0.
• [x] My code follows the WordPress coding standards.
• [x] My code has proper inline documentation.

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[rebeccahum]

@googlebot I signed it!

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[rebeccahum]

Thanks for the feedback @swissspidy. Are we good to go on this?

[swissspidy]

@rebeccahum Almost! WordPress.Security.EscapeOutput.OutputNotEscaped now flags that the output of phpversion() is not escaped.

[rebeccahum]

@swissspidy That's a false positive. We typically don't recommend escaping on built-in PHP functions (as the output cannot be modified by any hooks).

[swissspidy]

That's a false positive. We typically don't recommend escaping on built-in PHP functions (as the output cannot be modified by any hooks).

Then let's use // phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped to make PHPCS happy.

[rebeccahum]

@swissspidy Done, thanks!