tests/test-gendoc-sv.t

revlog: introduce an explicit NodeMap class for pure code

This class make the "pure" nodemap raise the same exception than the C-extension
one.

This is a step toward unifying nodemap and index, the class is not meant to
survive on the long run.

This work is part of a refactoring to unify the revlog index and the nodemap.
This unification prepare the use of a persistent nodemap.

There is a new `isinstance` call, it will be cleaned up in coming changesets.

Differential Revision: https://phab.mercurial-scm.org/D7312

#require docutils gettext

  $ $TESTDIR/check-gendoc sv
  checking for parse errors