docs: add invariants command and config docs #25

Job	Run time
build (aarch64-apple-darwin, macos-latest)	4m 15s
build (aarch64-unknown-linux-gnu, ubuntu-latest)	4m 19s
build (x86_64-apple-darwin, macos-latest)	4m 38s
build (x86_64-unknown-linux-gnu, ubuntu-latest)	3m 37s
release	8s
	16m 57s

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