Make markdown links consistent on cursor exits

Make the versions of link with and without * behave alike:

-   don't set the 0 location so that the cursor exits.
    Having a 0 in the title is bad because titles are short.

-   either open a new line at end for both, or for neither

    The only case where the newline is certain is for link definitions.
> Title is only one sentence usually, right?

Do you mean usually typed without exiting insert mode? If so, yes.

> UltiSnips will continue diffing your buffer on each keystroke until you exit outside of the snippet.

I don't clearly understand what you mean, but I'm sure it's something I have to learn about! I'll try to understand.