* Execute pys-on* events when triggered, not at load

Mimicing the behavior of Javascripts 'onLoad' event, we should
not be executing the use code at page-load time, only when
the event is triggered.

* Update examples to new syntax

* Fix merge issue

* Await running event handler code

* Restore pys-on* events with original behavior, deprecation warning

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* xfail toga example

* Add missing { (typo)

* Adjust callback chandling to make linter happy

* Change alpha to latest (#760)

* Don't create custom elements in main and fix various small issues on tests (#747)

* Create custom elements when the runtime finishes loading

* Remove xfails and fix repl integration test

* Fix commented ignore

* Address Antonio's comments

* Fix bad rebase

* Make ure to wait for repl to be in attached state before asserting content

* Move createCustomeElement up so it runs before we close the loader, xfail flaky d3 test

* Fix xfail

* [pre-commit.ci] pre-commit autoupdate (#762)

updates:
- [github.com/pre-commit/mirrors-eslint: v8.23.0 → v8.23.1](pre-commit/mirrors-eslint@v8.23.0...v8.23.1)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

* change documentation to point to latest instead of frozen alpha (#764)

* Toga example is xpass

* Correct 'xpass' to 'xfail' mark

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Peter W <34256109+pww217@users.noreply.github.com>
Co-authored-by: Fábio Rosado <fabiorosado@outlook.com>