Add publishEvent documentation and tests

[ndricimrr]

Description

Changes proposed in this pull request:

• add documentation for publishEvent feature
• Add example for compound scenario
• add example for wc scenario

Related issue(s)

Fixes #3860

Preview of docu section example:

[JohannesDoberer]

LGTM 👍

[smahati]

it's good as is, an alternative for publish event

[smahati]

yeah, I thought that would be bit of a stretch so thank you for trying :).

[smahati]

A general Question, in the comments there are references to filenames Like wcWebcomponent.js, is it for illustration or is it a reference to another example/sample?

[ndricimrr]

A general Question, in the comments there are references to filenames Like wcWebcomponent.js, is it for illustration or is it a reference to another example/sample?

wcComponent.js , firstChild.js , etc are just random file names I chose for the example as illustration.