How to treat .tpl syntax highlighting like php's syntax highlighting in PHPStorm

If you want to treat .tpl files in the same way as .php, then you will have to re-assign *.tpl pattern to PHP files type in Settings | File Types

P.S. This is IDE-wide setting and will affect all projects

In PhpStorm configuration settings:

 File->Settings->Editor->File Types->php-> + -> add *.tpl