split: take file patterns to limit selection on matching file patterns When splitting a big changeset, the user often wants to extract specific files from the changeset while leaving the others files intact. The split command can now be called with multiple file patterns. Only files that match one of the patterns will be shown in the interactive selection. The user will be able to create one or more commits with those files. When the user finishes splitting the matching files, a last commit will be made with the remaining of the files.

split: only accept explicit revision through the `-r` option We are about to introduce new non-optionnal arguments to defines files patterns. To avoid confusion and to be closer to the standard options, only accepts revisions with the `-r` option.

issue-6028: resolves 6028 - return (False, ".") instead of (False, '') Since 4.8, repo[] no longer takes an empty string, so we update to a valid with similar semantic. This value is strange and we should probably use an actual node ID here, however, this is an independent issue.