Log Message:
editors/tp-note: update to 1.22.7

Viewer: link to other docs with shorthand links, minor regr. fixes

New features:

* A shorthand link in a Tp-Note document e.g. `[text](tpnote:123)` is now
  expanded when being viewed. The renderer searches for a file starting
  with the sort-tag `123` on disk and displays the filename (without sort-tag).
  For example: a shorthand link to the file `123-My Animals.md` can be
  written as`<tpnote:123>` and the link will be displayed as `My Animals`.
* HTML rendition: The erroneous link path is now shown next to the error
  message.

(Minor) bug fixes:

* `file_ext: ''` is allowed again (regression introduced in v1.22.0)
* The viewer opens also (with an error message) in case of syntax errors
  in `file_ext:` or `sort_tag:`. These syntax errors had been mistakenly
  considered being fatal since v1.22.0.

Internal improvements:

* The link rewriting code is heavily refactored, simplified and easier to
  maintain.