Add button to automatically update URL

[dragonmaus]

Please add a button that will update a bookmark with the URL of the current tab.

One of the things I use buku for is managing my webcomic library, which requires frequent updates of the URL field of the bookmark.
Currently, to update a bookmark, I perform the following steps:

1. Ctrl-L
2. Ctrl-C
3. Click bukubrow icon
4. Click edit icon next to the topmost bookmark (which correlates most closely to the current page)
5. Tab twice
6. Ctrl-V
7. Enter
8. Click outside of the bukubrow popup

It would be nice to be able to do this with only a few clicks:

1. Click bukubrow icon
2. Click "Update URL" icon next to the topmost bookmark
3. Click outside of the bukubrow popup

Another possibility would be adding "Update from Tab" buttons to the fields in the edit dialogue. This would also be acceptable, as the most cumbersome part of the process is the copy/paste. (This might actually be better UX, despite adding a click or two.)