Update Search.php

$string = preg_replace('/[._-]+/', '', $string);

Ex :
Product's name : Saint-leon
Search : leon => 0 result

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$string = preg_replace('/[._-]+/', ' ', $string);
Ex :
Product's name : Saint-leon
Search : leon => 1 result

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I think that thus the search is more relevant
Merge pull request #587 from ChristopheBoucaut/patch-2

[-] CORE : Search terms can now have dashes in Search.php