[Audacity-quality] Hyphenated "plug-in"

[Steve t. F. <ste...@gm...>]

There is one place that (currently) we *must* still use "plug-in"
rather than "plugin" and that is in the header of Nyquist plugins.
http://wiki.audacityteam.org/wiki/Nyquist_Plugins_Reference#Required_plugin_header_lines
I have corrected that in the wiki (after it had recently been "modernised").

I've not found the incorrect use of ";nyquist plugin" in the manual,
but perhaps someone more expert with the manual (Gale, Peter, Bill?)
could check.

It is inconsistent and confusing that we now use the one word version
"plugin" everywhere except in the Nyquist plugin header, and is very
likely to cause errors (such a the three that I have just corrected).

Either we will need to remain ever vigilant about this inconsistency
(and accept that it will probably catch out users that try to write
plugins), or (better in my opinion) allow ";nyquist plugin" as a valid
alternative in version 4 plugins (deprecating the old "plug-ins"
spelling, but still allowing it for now).

If we are to do that, I think it should be done for Audacity 2.1 (the
first version to support version 4 Nyquist plugins) rather than wait
for version 5 Nyquist plugins. This is a change that I can make and I
think it carries very low risk.

Steve