I often find myself wanting to navigate paginated web pages 
(e.g. <https://media.libreplanet.org/videos?page=4>), or to go up 
or all the way up when visiting a web page, which is why I added 
these functions to my eww.

Does this change make sense?  If so I will amend the patch to 
include tests, doc and bug number.

Note that there seem to be currently no tests for eww, so I will 
need to create a new file.

BTW a newbie question: CONTRIBUTE mentions the commit message 
should include bug number, but when I send a patch like this a bug 
number is only generated afterwards.  Does this mean I should 
report a bug, wait for the item to be created in debbugs, before 
sending a patch for the bug?

Thanks.