$agent->is('Chrome') returns true for edge

Hello, with version `2.6.0` on php 7.0, Edge

Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/52.0.2743.116 Safari/537.36 Edge/15.15063

is detected as Chrome with `$agent->is('Chrome')`

Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/59.0.3071.109 Safari/537.36

The 2 are distinguished correctly by http://php.net/manual/en/function.get-browser.php, so I guess it's something with this library, and the method `$agent->browser()` returns the correct browser name.

Why this discrepance? Is it intended? Does the documentation need an update?

Thank you

Start by tracing the $agent->is('Chrome') and $agent->browser() entry points and compare their handling of the two supplied user-agent strings. Determine whether Edge should be excluded from the Chrome match, then verify the intended behavior with the project's existing tests or documentation; done means the distinction is resolved and documented or covered by a regression test.

Written by the indexing model from the issue text.