Add support for Microdata

[toastal]

See: https://html.spec.whatwg.org/multipage/microdata.html

Also includes some English orthographic fixups in a separate (droppable) commit.

¹

Footnotes

1. Please consider giving up MS GitHub or offering a non-proprietary, non-US-corporate-controlled mirror for this free software project. I wish to delete this Microsoft account in the future, but I need more projects like this to support alternative methods to send patches & contribute. ↩

[toastal]

These build errors also happen on the default branch. Just did a fresh checkout to find:

File "ppx/tyxml_ppx.ml", line 381, characters 18-65:
381 |   | Pexp_function (params, constraint_, (Pfunction_body content)) ->
                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Error: This pattern matches values of type 'a * 'b * 'c
       but a pattern was expected which matches values of type case list
Generating: index.html  

I have been using this branch in a Nix overlay for 2 weeks now.

[toastal]

It appears to me dune test fails starting at 7b11831 from #340

[toastal]

@smorimoto

[smorimoto]

Could you please rebase this?

[toastal]

Local said I was up to date. I will force push again… it could have been a miss timing.

[toastal]

$ git checkout microdata 
Switched to branch 'microdata'
$ git pull --rebase upstream master
From https://github.com/ocsigen/tyxml
 * branch              master     -> FETCH_HEAD
Current branch microdata is up to date.
$ dune clean
$ dune test --stop-on-first-error
File "ppx/tyxml_ppx.ml", line 381, characters 18-65:
381 |   | Pexp_function (params, constraint_, (Pfunction_body content)) ->
                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Error: This pattern matches values of type 'a * 'b * 'c
       but a pattern was expected which matches values of type case list

@smorimoto this is the same error the CI was giving