How to create a snippet for this?

Hello guys,

Can someone give me a little help?

I have this plugin installed:
https://github.com/lesterchan/wp-postratings

But it shows the rating percentage like this:
50.00% instead of 50%
33.33% instead of 33%
etc...

My idea is to remove decimals. I know how to fix this changing in the file:
https://github.com/lesterchan/wp-postratings/blob/master/wp-postratings.php

From:

$value = str_replace("%RATINGS_PERCENTAGE%", number_format_i18n($post_ratings_percentage, 2), $value);

Code (markup):

To:

$value = str_replace("%RATINGS_PERCENTAGE%", number_format_i18n($post_ratings_percentage), $value);

Code (markup):

But I don't want to change directly in the plugin file because I don't want to loose changes when I upgrade the plugin. So I want to use a plugin to add a snippet to fix this. Something like this plugin.

But I don't have enough knowledge how to do that.

Can someone help me?

Thanks in advance