Log Message:
Updated package to latest version, 4.0.0. Changes include:

====== Features ======
* A new PPX has been added that allows to use tyxml with the HTML/SVG syntax, \ 
using the markup library (contribution by Anton 'aantron' Bachin).
* New Format-based printers are available, both as functors and has `pp` \ 
functions in the various implementations. Old printers are deprecated.
* Toplevel printers are now available for the `tyxml` library.
* The `str` library has been replaced by `re`.
* Various attributes arguments have been simplified. In particular:
  * Constants arguments have been removed
  * `` `On|`Off `` arguments are now replaced by booleans.
  * Some arguments now use an option type.

* XML comments are now properly serialized (without escaping but with sanitization).

====== Elements and attributes ======
* Add srcset and sizes attributes (contribution by Stéphane 'slegrand45' Legrand).
* The arguments of the `sandbox` attributes are now more consistent \ 
(contributino by Anton 'aantron' Bachin).
* Various SVG attributes and elements are now properly named (contributino by \ 
Anton 'aantron' Bachin).
* Add inputmode attribute.

====== Documentation ======
* Both the API documentation and the manual have been completely rewritten! Do \ 
not hesitate to read them and provide feedback.
* Various examples have been added in the `example/` directory. (basic_website \ 
contributed by Edgar 'fxfactorial' Aroutiounian).

====== Renaming and deprecations ======
* Files in the `tyxml` library are now packed in a `Tyxml` module.
  If you were using one of `Html5`, `Svg` and `Xml` module, simply open `Tyxml`.
* All Html5 modules are now named Html
* Various attributes and elements have been renamed. The original versions have \ 
been kept and marked deprecated.
* Various elements that were both deprecated in the HTML specification and not \ 
usable due to typing constraints have been removed.