Update the token precedence documentation to be clearer about plugins vs. modules

[briantist]

SUMMARY

See:

• https://github.com/ansible-collections/community.hashi_vault/issues/327#issuecomment-1312688883

Although the options on modules vs. plugins do correctly show whether vars/env/ini are supported, the note in the description for the token option explains precedence additionally to cover token file loading and low-precedence env vars.

This could be confusing when shown on a module because it still includes Ansible vars. We can update that to be more clear by specifying which vars work where.

ISSUE TYPE

• Documentation Report