This would make more sense in user code:
```rs
Yaml::load_from_str("foo"); // Explicit that we're parsing YAML
load_from_str("foo"); // Too implicit, too generic, may be from another
lib
```
Plus, this mirrors `MarkedYaml`'s behavior.
* Make `YamlLoader` generic on the type of the `Node`. This is required
because deeper node need to have annotations too.
* Add a `LoadableYamlNode` trait, required for YAML node types to be
loaded by `YamlLoader`. It contains methods required by `YamlLoader`
during loading.
* Implement `LoadableYamlNode` for `Yaml`.
* Take `load_from_str` out of `YamlLoader` for parsing non-annotated
nodes. This avoids every user to specify the generics in
`YamlLoader::<Yaml>::load_from_str`.
These tests were sucecssfully converted to Rust files to include and are
no longer necessary in this repository.
Should they become relevant again in the future, they can always be
checked out from a previous commit.
This is a huge commit that cannot easily be broken down as it contains
fixes for the next ignored test in the suite which, one fixed, broke
tests that used to pass and were only then fixed.
There is also a substantial amount of comments that were added,
especially around `SimpleKey`. Minor improvements around the code were
added and I did not bother making a separate commit for them.
Overall, that commit fixes 7 tests from the matrix that were related to
the handling of simple keys.
