Add --custom-function parameter to check

[umutphp]

In one of the projects that I have been working for a while, there are some legacy custom dump functions created and used frequently by the team. A sample function is;

function pre_dump( $var ) { echo '<pre>'; var_dump( $var ); echo '</pre>'; }
The check tool can not find the usage of such kind of functions. A sample usage might be;

$ ./vendor/bin/var-dump-check --no-colors --tracy --custom-function pre_dump,echo_dump .

[grogy]

Hello,

it makes me sense. Thanks for PR, I will review it

[grogy]

It looks very good. You have some comments in PR. This issue i close, because PR will be merged. Thank you