Pdf support

[Sowasvonbot]

Enable pdf as command line flag for --output-formats and render the html-document to a pretty printed pdf

[mhatzl]

Converting supported.um to PDF prints the following error message:

thread '<unnamed>' panicked at C:\Users\ManuelHatzl\.cargo\registry\src\index.crates.io-6f17d22bba15001f\headless_chrome-1.0.8\src\browser\transport\web_socket_connection.rs:117:25:
Got a weird message: Close(Some(CloseFrame { code: Normal, reason: "" }))

The PDF is correctly generated, but I guess headless chromium fails at cleanup?

[Sowasvonbot]

Converting supported.um to PDF prints the following error message:

thread '<unnamed>' panicked at C:\Users\ManuelHatzl\.cargo\registry\src\index.crates.io-6f17d22bba15001f\headless_chrome-1.0.8\src\browser\transport\web_socket_connection.rs:117:25:
Got a weird message: Close(Some(CloseFrame { code: Normal, reason: "" }))

The PDF is correctly generated, but I guess headless chromium fails at cleanup?

This Bug is known in headless-chrome: rust-headless-chrome/rust-headless-chrome#441
Will be fixed in the next release

[mhatzl]

looks good for the initial pdf support.
The CloseFrame error is fixed in the main branch of headless chromium, but this version is not yet published.
We internally agreed to wait for the official release, because the pdf is rendered correctly already anyways.