helptext: mention in `hg help config` that `.hg/hgrc-not-shared` is consulted Recently we added `.hg/hgrc-not-shared` which is a config file which won't be shared with shares when share-safe mode is enabled. Irrespective of whether we are using share-safe or not, we consult this file now. Let's document that. Differential Revision: https://phab.mercurial-scm.org/D9412