Align viewcode links on the right

[azmeuk]

The sphinx viewcode extension adds [source] links near python object signatures.

The link is displayed under the signature, but I think this would be nicer if it were aligned on the right side like it does in alabaster:

What do you think?

[lepture]

The reason I put [source] in a new line is that sometime, the class name may be too long, and then it will mess up with the [source] link.