Discourage reader from deleting folders you dont wanna delete in compilation/clean

[legoaggelos]

https://javabook.mccue.dev/compilation/clean
might want to add a (potentially funny) footnote that u shouldnt run this on a folder that u dont want to delete, such as root or C:// etc. "might sound obvious, but dont run this on root, else all your data is gone, all of it"
or sth like "if you want to see the world burning, ask a friend to run rm -rf ~" or similar

originally suggested in the TJ discord by zabuzard.