Add a sniff to fix *Interface already announced in *Class

Problem/Motivation

For example: For the class Bar blow, FooInterface is already announced in class Foo

Interface FooInterface {

}

Interface BarInterface {

}

class Foo implements FooInterface {

}

class Bar extends Foo implements FooInterface, BarInterface {

}

Proposed resolution

https://github.com/pfrenssen/coder/pull/99

Remaining tasks

User interface changes

API changes

Data model changes

Release notes snippet