* rustdoc: Fix fontface broken link error
* Correct link to `Font`
* Reduce the diff a bit
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Co-authored-by: Martin Robinson <mrobinson@igalia.com>
Instead of using a simple `Atom` to identify a local font, use a data
structure. This allows us to carry more information necessary to
identify a local font (such as a path on MacOS). We need this for the
new version of WebRender, as fonts on MacOS now require a path.
This has a lot of benefits:
1. We can avoid loading fonts without paths on MacOS, which should
avoid a lot of problems with flakiness and ensure we always load the
same font for a given identifier.
2. This clarifies the difference between web fonts and local fonts,
though there is more work to do here.
3. This avoid a *lot* of font shenanigans, such as trying to work
backwards from the name of the font to the path of the font we
actually matched. In general, we can remove a lot of code trying to
accomplish these shenanigans.
4. Getting the font bytes always returns an `Arc` now avoiding an extra
full font copy in the case of Canvas.
This uses a (very simple) Win32 API call to enumerate font
families available, and load them as byte buffers.
The font rasterization itself is done by freetype.
This gets Servo + WR + Windows working, but should be improved
by adding a proper implementation that matches fonts correctly
and also uses DirectWrite (or GDI) to handle font rasterization.
