#32 - Implementation completed with rich unit tests coverage.
- manual.md contains a simple example of the new feature
- support for undocumented `\[0-3]` for the requester of the feature ;-)
- finetuned the 'modified' sorting method - not the folders are ordered alphabetically, as the standard Obsidiand sort by 'modified date' does
- finetuned the 'created' sorting method in the same way as 'modified'
- added some initial content to syntax-reference.md ;-)
- extended the 'advanced modified' sorting method to also support the edge-case secondary sorting methods for groups