See commits for details. Closes #1837, #5880, #7822, #8101, #8821, #9367, #9382, #9378, #4731
This PR drastically improves the documentation by improving the sidebars and adding a GitHub icon. Fixed: https://github.com/puppeteer/puppeteer/pull/9176 Fixed: https://github.com/puppeteer/puppeteer/issues/9173 