Test if the docs are built successfully when something inside docs/ is modified

[niketagrawal]

When new changes are introduced to main via a feature branch using a pull request, tests are run automatically on the feature branch to ensure that the code changes do not break the existing functionality of aeolis. While there are no specific tests for the docs like the rest of the code, the docs are expected to build successfully every time anything inside the directory docs/ is modified.

This docs build test can be setup to run automatically on pull requests to main when there is a change inside docs/ using a separate GitHub actions workflow.