[web-php][PR #384] - Fix typo in changelog

You can view the Pull Request on github: https://github.com/php/web-php/pull/384 Opened By: lpd-au Pull Request Description: This relates to https://github.com/php/doc-en/pull/274. The [PHP 7.1.0 changelog](https://www.php.net/ChangeLog-7.php#7.1.0) has the following entry: > Add sig**n**info to pcntl_signal() handler args (Bishop Bettini, David Walker) As described in the PR above, the pcntl_signal docs page incorrectly used both the spelling siginfo and the typo signinfo interchangably to represent this one argument. The source itself always uses the former: https://github.com/php/php-src/blob/22bf92564ca2ff7e4827e69c364942c4291931dc/ext/pcntl/pcntl.c#L1287 Now the docs have been fixed to consistently use this spelling, it would be good if the changelog did too; a typo in the feature name itself makes it difficult to search for.