shelve: add 'changes to' prefix to default shelve message The shelved changes _could_ perhaps be amended to the parent changeset but it _is_ not the parent changeset. Using the description from the parent changeset is thus wrong and confusing. Instead, add a 'changes to' prefix.

shelve: mention FILE options in help Shelve do normally take a list of files or patterns to shelve and the command summary should thus show [FILE]... Note: --delete is a bit special and interpret the parameters as a list of shelve names. This change makes that even less obvious from the help. Too bad - we can't please everyone.

shelve: mention walk options in help

shelve: really pass publicancestors to changegroupsubset - not the parents publicancestors returned the parents of the public ancestors ... and changegroupsubset used the parents of these as base for the bundle. That gave bundles with one layer of changesets more than necessary.

shelve: publicancestors do not have to visit nullrev Not visiting nullrev seems more correct and might be a minor optimization.

localrepo: make it clear that changegroupsubset doesn't take bases but roots changegroupsubset will take the parents of the roots to find the bases. Other parts of Mercurial do not expect that, and a result of that is that some bundles contain more changesets than necessary. No real changes here - just renaming a parameter to document what it is.