Move modifier Keys under a Modifiers subtype to call out that they behave differently

[tristanlabelle]

This was causing developer confusion and a bug report "In tests, sending Keys.control does not WM_KEYUP".

[jasdev]

Hmm with this change I can’t simulate Alt being held while clicking since another key is needed in conjunction — i.e. having trouble updating this test after bumping the -webdriver SHA in the project. 🙏🏽

[tristanlabelle]

@jasdev Since this change, you would have to explicitly add releaseModifiers: false to your sendKeys call.

[jasdev]

@tristanlabelle: Right but afaict there’s no way to send .alt by itself without another key!

[tristanlabelle]

@jasdev Yes! sendKeys(Keys.Modifiers.alt, releaseModifiers: false)
(I wanted to add more friction for this API usage since it can be surprising, however we could add parameters to click() to combine with alt/ctrl/shift more easily)