Improve the doc on `~/.stack/global-project/stack.yaml` (#3141)
Improve the doc on `~/.stack/global-project/stack.yaml` (#3141)

Fix #3140
anton-dessiatov/stack,mrkkrp/stack,martin-kolinek/stack,anton-dessiatov/stack,mrkkrp/stack,martin-kolinek/stack,MichielDerhaeg/stack,juhp/stack,juhp/stack,MichielDerhaeg/stack