Changes to Pathauto

I've reviewed the current state of the pathauto module. 
As I'm new to D8 development, I did some minor changes I saw during the reading of the code.
Looks like https://github.com/md-systems/pathauto/blob/8.x-1.x/config/install/pathauto.settings.yml also needs to be fixed. The ignore_words key is duplicate in the default config.