Improve interlinking of archiving/compression modules docs.

- Remove duplicated list of links to the other modules from each
  module’s doc (people can already go up to library/archiving and
  there they can see the list).

- Link to shutil high-level operations.

Reviewed by Nadeem Vawda in #6715.
diff --git a/Doc/library/shutil.rst b/Doc/library/shutil.rst
index 8b4aabb..3b44774 100644
--- a/Doc/library/shutil.rst
+++ b/Doc/library/shutil.rst
@@ -31,6 +31,8 @@
    are not copied.
 
 
+.. _file-operations:
+
 Directory and files operations
 ------------------------------
 
@@ -181,7 +183,7 @@
    (*srcname*, *dstname*, *exception*).
 
 
-.. _shutil-example:
+.. _shutil-copytree-example:
 
 copytree example
 ::::::::::::::::
@@ -248,6 +250,9 @@
 Archiving operations
 --------------------
 
+High-level utilities to create and read compressed and archived files are also
+provided.  They rely on the :mod:`zipfile` and :mod:`tarfile` modules.
+
 .. function:: make_archive(base_name, format, [root_dir, [base_dir, [verbose, [dry_run, [owner, [group, [logger]]]]]]])
 
    Create an archive file (such as zip or tar) and return its name.
@@ -375,6 +380,7 @@
    .. versionadded:: 3.2
 
 
+.. _shutil-archiving-example:
 
 Archiving example
 :::::::::::::::::
@@ -400,5 +406,3 @@
     -rw------- tarek/staff    1675 2008-06-09 13:26:54 ./id_rsa
     -rw-r--r-- tarek/staff     397 2008-06-09 13:26:54 ./id_rsa.pub
     -rw-r--r-- tarek/staff   37192 2010-02-06 18:23:10 ./known_hosts
-
-