doc/common.txt

clfilter: ensure context raise RepoLookupError when the revision is filtered

Currently the code path of `changectx(filteredrepo, rev)` call
`filteredrepo.changelog.node(rev)`. When `rev` is filtered this raise an
unhandled `IndexError`. This case now raise a `RepoLookupError` as other
error case do.

.. Common link and substitution definitions.

.. |hg(1)| replace:: **hg**\ (1)
.. _hg(1): hg.1.html
.. |hgrc(5)| replace:: **hgrc**\ (5)
.. _hgrc(5): hgrc.5.html
.. |hgignore(5)| replace:: **hgignore**\ (5)
.. _hgignore(5): hgignore.5.html