Update Ruter docs

[tjorim]

Description:
Default name was missing and offset is 1 by default.

Since this was introduced in 0.83 (currently beta) I believe this PR should get milestone 0.83 as docs for a new component.

Pull request in home-assistant (if applicable): home-assistant/core#18678

Checklist:

• Branch: next is for changes and new documentation that will go public with the next home-assistant release. Fixes, changes and adjustments for the current release should be created against current.
• The documentation follows the standards.

[ludeeus]

I think the offset value is a "bug" in the code, and that is should have been 0, will test this.

[tjorim]

Then we should either change the behaviour in the code or clarify how the offset value works. (Is it in minutes? Does it only show departures more than x minutes from now?)

[ludeeus]

Its the placement in the dict returned from the API.
So a offset of 0 should give you next departure, 1 should be the one after that

Example:

0: 15:56
1: 16:04
2: 16:11

Setting up a dev env now to see if confirm that I screwed up..

[ludeeus]

@tjorim Made a PR to set default value to 0 home-assistant/core#18678