Previously, we were used /usr/share/doc/rust{,-doc}/html as a default
source, assuming that it would contain the standard library
documentation. This is true if the user installed the Rust
documentation manually or using a package manager. If they use rustup
instead, the documentation is placed in a subdirectory of ~/.rustup.
With this patch, we call `rustc --print sysroot` to determine the
installation directory of the currently activated Rust toolchain –
either the system Rust installation or a Rust installation managed by
rustup. We then use `$(sysroot)/share/doc/…` as a default path for the
standard library documentation (with /usr as a fallback if the call to
rustc does not return a valid path).
This patch release adds basic logging output and a new `-e`/`--examples`
option to extract only the examples from the documentation. It also
fixes a bug when displaying the documentation for a function.
Previosuly, we always used the selector ".docblock.type-decl" to select
the definition for an item. But this did not work for functions.
Therefore we change the selector to "pre.fn" for functions.
Robin Krahl