issue-#178 renaming Host/Docu/Prefs to Prefs-Dialog

[Josef Templ]

I have created this https://redmine.blackboxframework.org/issues/178 for cleaning up the file list produced by Info->Repository.
It is the same fix as for Tab-Dialog and Links-Dialog.

At the time of introducing this docu file I (we) were not aware of the naming convention to be applied in such cases.
Robert pointed out the problem in issue-#175.
This fixes it.

Please see also my related posting for Tab-Dialog at https://forum.blackboxframework.org/viewtopic.php?f=50&t=632&start=60#p6500.

I have checked all subsystems and did not find any remaining problems of this kind.

Diffs are at https://redmine.blackboxframework.org/projects/blackbox/repository/diff?utf8=%E2%9C%93&rev=77ac40be509558e3cffa7c31b7b82005fa78cd87&rev_to=68b54a7d34c32b598c90c121b041957d44afd75d.
The diff shows only the renaming of the docu file. In addition, references to the renamed file have been updated at two places, (1) in the Preferences dialog and (2) in the Coroutines docu.

- Josef

[Robert]

Since I can't imagine that this needs much discussion I am calling the vote straight away.