Rust

Improve the documentation, the CI and fix Clippy #387

Job	Run time
Run the heed examples (ubuntu-latest)	32s
Check all the features of the heed project (ubuntu-latest)	14s
Check all the features of the heed3 project (ubuntu-latest)	25s
Run the heed examples (macos-latest)	23s
Check the heed3 project (ubuntu-latest)	29s
Check all the features of the heed project (macos-latest)	20s
Check all the features of the heed3 project (macos-latest)	33s
Check the heed3 project (windows-latest)	1m 2s
Check the heed3 project (macos-latest)	20s
Ensure the heed project is formatted	13s
Ensure heed3 is not erasing heed	2s
Run the heed3 examples (ubuntu-latest)	23s
Run the heed3 examples (macos-latest)	25s
Test the heed project (ubuntu-latest)	44s
Test the heed project (windows-latest)	1m 46s
Test the heed project (macos-latest)	29s
	8m 20s

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