Docs: Replace multiple single line comments with multi-line comments.
This changeset updates various comments as per WordPress PHP Inline Documentation Standards.
See https://developer.wordpress.org/coding-standards/inline-documentation-standards/php/#5-inline-comments.
Follow-up to [56174], [56175], [56176], [56177], [56178], [56179], [56180], [56191], [56192], [56193], [56194].
Props costdev, audrasjb.
See #58459.
Built from https://develop.svn.wordpress.org/trunk@56195
git-svn-id: http://core.svn.wordpress.org/trunk@55707 1a063a9b-81f0-0310-95a4-ce76da25c4cd
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