config/cloud.cfg.d/README says "All files" rather than "*.cfg"

Bug Description

The README file installed in /etc/cloudinit/cloud.cfg.d/ currently says "All files in this directory will be read by cloud-init"... but actually cloud-init only reads files whose names end in ".cfg".

The upstream source for this README file appears to be root/config/cloud.cfg.d/README, i.e.
https://git.launchpad.net/cloud-init/tree/config/cloud.cfg.d/README

The code that does the reading of the files in that directory seems to be the read_conf_d() function found in util.py, e.g. currently starting at
https://git.launchpad.net/cloud-init/tree/cloudinit/util.py#n1011

Thanks for filing the issue to help make cloud-init better.

https://github.com/canonical/cloud-init/pull/106

This bug is believed to be fixed in cloud-init in version 19.4. If this is still a problem for you, please make a comment and set the state back to New

Thank you.

Tracked in Github Issues as https://github.com/canonical/cloud-init/issues/3510