Allow configuration of explicit Spring REST Docs snippets

[jbrugge]

I see that the SpringRestDocsExtension.java has a method, withExplicitSnippets, but I don't see any way of using it.

I would like to be able to include the "links.adoc" snippet that Spring REST Docs can produce, in addition to the other default snippets.

[RobWin]

You could use the import files extension to include the file.
Otherwise you could create a PR.