Enhance wc/guard-super-call with fix

[stramel]

It should be relatively simple to add a fix for wc/guard-super-call

Take a simple error state such as:

connectedCallback() {
  super.connectedCallback();
  this.setAttribute('bar', 'baz');
}

and change it to this:

connectedCallback() {
  if (super.connectedCallback) {
    super.connectedCallback();
  }
  this.setAttribute('bar', 'baz');
}