Add option to avoid IDs

[felquis]

In the session IdWithExtraneousSelector the last line is about:

Even better would be to never use IDs in the first place.

We don't have an option to avoid IDs, would be great to have one :)

[anselmh]

If you don’t want to support this by default (I’d love to set this also as option), #161 could help here.

[sds]

Thinking about this, it seems like IdWithExtraneousSelector wasn't being opinionated enough—using IDs in selectors is a smell and should be avoided entirely.

I've renamed IdWithExtraneousSelector to IdSelector and modified its behavior to report a lint if an ID ever appears in a selector (and thus made it stricter) in aea47bb.

[felquis]

I'm sorry @anselmh I don't have any experience with Ruby to help :/