yy on line without trailing newline should insert a newline on p

[alisonatwork]

If you open a new file and type a line of text without hitting enter, then yy, then p, it pastes the current line's text immediately to the right of the current line instead of on the next line.

Bug can be reproduced by adding the following to y y.test.ts:

        {
            from: 'one lin[]e',
            inputs: 'y y p',
            to: 'one line\n[]one line',
        }