-Start at current directory
-Look inside all sub-directories to see if there is a bin/activate.fish script
-If not found, look in the parent directory, and continue up the file path until one is found, or give up

Covers cases like:
-Virtual environment is in a .venv or venv folder (any folder name is supportd) in the current working directory
-Virtual environment is in a parent folder of the current working directory
-Virtual environment is in the current working directory

redirect error to /dev/null

Redirect to null error message from find