* Begin simple invariant docgen script

* Support Echidna tests in invariant docgen

* Use custom natspec tags for invariant doc comments

* Handle multi-line headers for linting purposes

* Restack

* Upstack

* New doc

* New doc

* Add test file name to link in docgen script

* Relative URL path

* Use `path.join`

* Add task to `contracts-bedrock` workflow to check diff of `invariant-docs`

* Generate a table of contents for invariant docs