Docs: Remove block quotes
Problem to solve
We do not have an entry in our style guide regarding block quotes (>): https://docs.gitlab.com/development/documentation/styleguide/#text-formatting
But during a quick search for block quotes in the docs, it seems like we're almost always using it instead of our official alert box formatting: https://docs.gitlab.com/development/documentation/styleguide/#alert-boxes
We should review our docs sets and remove block quotes throughout. One page where it is acceptable is user/markdown.md, which it is used to differentiate between plaintext and rendered examples.