Zend.Debug.CodeAnalyzer: soft deprecate the sniff

See 58.

This commit _soft_ deprecates the sniffs with a `@deprecated` annotation. This will get a mention in the changelog.

Hard deprecation will follow in a future 3.x minor as per 188.

Author: jrfnl

src/Standards/Zend/Sniffs/Debug/CodeAnalyzerSniff.php

@@ -6,6 +6,8 @@
  * @author    Greg Sherwood <gsherwood@squiz.net>
  * @copyright 2006-2015 Squiz Pty Ltd (ABN 77 084 670 600)
  * @license   https://github.com/PHPCSStandards/PHP_CodeSniffer/blob/master/licence.txt BSD Licence
+ *
+ * @deprecated 3.9.0
  */
 
 namespace PHP_CodeSniffer\Standards\Zend\Sniffs\Debug;