Adding back empty sample hooks

Hi folks,

Would there be interest in adding back the sample hooks that were
removed in [8d714b11df][1]. I think that they are helpful if only as a
quick reference showing what hooks are possible. (As well spelling
receive incorrectly is a source of confusion (I think), but that's not
a good argument.)

Thanks!

Whymarrh

    [1]:https://github.com/git/git/commit/8d714b11df2b65e5f4272c1616e561930010be90