* feat: add transparent option to WebContents
* feat: add transparent attribute to webview
* test: add tests for webview transparent attribute
* docs: add transparent attribute to webview docs
* fix: run tests on macOS only
* refactor: remove unneeded html tag
* fix: only apply transparent option to guests
* refactor: correct comment
* refactor: use opaque instead
Retains current webview behaviour by default.
* fix: correct variable name to guest_opaque_
* refactor: use transparent webpreference
* docs: remove unused web preference
* fix: uncomment condition for transparency test
* docs: converted to list format and linked to MDN
* fix: make webviews transparent by default again
* fix: rebase error
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Co-authored-by: Cheng Zhao <zcbenz@gmail.com>
