Hi Guix,

The attached patch adds the emacs-semantic-refactor package.

When reviewing this patch some particular things to look out for/questions 
I have:

0) There are different sections in the (gnu packages emacs-xyz) module 
that are delineated by comments (e.g. Emacs Hacking, Web Browsing, and 
Miscellaneous). I've added the definition of emacs-semantic-refactor near 
the end of the file in the Miscellaneous section. I wonder if this is 
correct or if it should go in the Emacs Hacking section. Paredit, which 
would be used in similar scenarios to semantic-refactor is in the Emacs 
Hacking section.

1) The upstream source contains a number of animated gif files 
demonstrating usage in the srefactor-demos directory. I do not see a build 
process for these, and assume they were created by hand. Are we free to 
distribute these in Guix?

2) semantic-refactor has an optional integration with projectile whose 
availability is checked for with (featurep 'projectile). I have not added 
projectile as an input or propagated-input. Is this OK?

3) I'm still new to writing package definitions, so extra scrutiny is 
warranted, particularly for the synopsis and description.

All the best,
Jack