doc: Channel subsection order?

[zimoun <zimon.toutoune@gmail.com>]

Dear,

I was re-reading the section about Channels and the subsections do not
appear to me "logical".  Currently, it is:

  1. Channel Authentication
  2. Using a Custom Guix Channel
  3. Specifying Additional Channels
  4. Declaring Channel Dependencies
  5. Package Modules in a Sub-directory
  6. Specifying Channel Authorizations
  7. Primary URL
  8. Writing Channel News
  9. Replicating Guix

and to me, the progression when reading is smoother with this order:

  1. Using a Custom Guix Channel
  2. Specifying Additional Channels
  3. Channel Authentication
  4. Declaring Channel Dependencies
  etc.

The examples read more naturally:

#1
     ;; Tell 'guix pull' to use my own repo.
     (list (channel
             (name 'guix)
             (url "https://example.org/my-guix.git")
             (branch "super-hacks")))

#2
     ;; Add my personal packages to those Guix provides.
     (cons (channel
             (name 'my-personal-packages)
             (url "https://example.org/personal-packages.git"))
           %default-channels)

#3
     (channel
       (name 'my-channel)
       (url "https://example.org/my-channel.git")
       (introduction
        (make-channel-introduction
         "6f0d8cc0d88abb59c324b2990bfee2876016bb86"
         (openpgp-fingerprint
          "CABB A931 C0FF EEC6 900D  0CFB 090B 1199 3D9A EBB5"))))

than: starts by #3 and goes to #1 after.

Other said, starting by Authentication gives the false impression that
Channels have to be authenticated (with gpg keys and so on); which
means (at least to me): it is complicated.  And it is not, both:
necessarily authenticated and complicated. : -)

All the best,
simon