Fix bug with linking to Muse project files when muse-file-extension is nil
* lisp/muse-project.el (muse-project-resolve-directory): New function
that figures out the directory part of the path that provides a link to
a page.
(muse-project-resolve-link): Expand docstring. Use the new function.
Don't call muse-publish-link-file, because that does the wrong thing
when we have muse-file-extension set to nil. Thanks to Sebastian
Obermanns for the report.
* lisp/muse-publish.el (muse-publish-link-name, muse-publish-link-file)
(muse-publish-link-page): Add docstrings so that I can remember what
each of these things do.
* lisp/muse.el (muse-page-name): Improve docstring.