## Motivation
The documentation under https://tracing.rs/tracing/ is missing CSS
styles. Fixes#2444
## Solution
Used the `--html-in-header` rustdoc flag instead of `--extend-css`.
Converted the css file into an html file.
This branch adds a warning header to documentation built from the
`master` branch, noting that this is _not_ documentation for the release
version, and suggesting that users refer to docs.rs for the release
documentation instead. Netlify is configured to include this header when
building documentation. This should make it clearer that documentation
built from `master` does _not_ document the currently documented release
versions on crates.io.
I'm very far from a web developer, so it's almost certainly possible
that the warning header could look nicer. I'll happily take suggestions
for improving the styling, but at least this gets the point across.
Additionally, I've added a [`noindex` meta tag][1] to the documentation's
HTML `<head>`. This should prevent it from showing up in search engines,
so that when people Google tracing APIs, they end up on the docs.rs
documentation, rather than the `master` branch dev docs.
You can see what it looks like in the netlify deploy preview, but basically,
it looks like this:

Closes#1592
[1]: https://developers.google.com/search/docs/advanced/crawling/block-indexing
This changes the logo to a wordmark. This should be consistent
with the ones for all the other Tokio crates, when we add them
elsewhere.
Signed-off-by: Eliza Weisman <eliza@buoyant.io>
This branch adds an SVG splash graphic to the main
repository readme, based on the illustration on tokio.rs.
I thought about sticking a big "As seen in rustc!" on there,
and we *could* still do this...
Signed-off-by: Eliza Weisman <eliza@buoyant.io>
Now that the new https://tokio.rs is live, we can add the new Tracing
logo to the RustDoc!
I also added a couple missing `html_root_url` attributes in published
crates.
Signed-off-by: Eliza Weisman <eliza@buoyant.io>