doc: use anonymous links
Per docs:
http://docutils.sourceforge.net/docs/ref/rst/restructuredtext.html#anonymous-hyperlinks
We should use them pretty much everywhere, but since there's no
such tool to give us "linting" info - let's at least silence the
warnings at places where it is messing our stderr:
/home/praiskup/rh/projects/copr/copr/doc/user_documentation.rst:4: WARNING: Duplicate explicit target name: "here".
/home/praiskup/rh/projects/copr/copr/doc/user_documentation.rst:4: WARNING: Duplicate explicit target name: "blog post".
/home/praiskup/rh/projects/copr/copr/doc/user_documentation.rst:4: WARNING: Duplicate explicit target name: "blog post".
/home/praiskup/rh/projects/copr/copr/doc/user_documentation.rst:4: WARNING: Duplicate explicit target name: "blog post".
/home/praiskup/rh/projects/copr/copr/doc/user_documentation.rst:4: WARNING: Duplicate explicit target name: "blog post".
/home/praiskup/rh/projects/copr/copr/doc/user_documentation.rst:4: WARNING: Duplicate explicit target name: "blog post".