Deprecate __keywords__ internal function?

[Rik]

2/24/15

All,

Is there any objection to getting rid of the __keywords__ function?  It is
located in help.cc and returns a list of keywords for which there is help
text.  However, this is not the full list of keywords as returned by the
iskeyword() function.  The latter function is based directly on what the
parser knows as keywords and includes the new classdef keywords like
"properties" for which no documentation has yet been written.

The only place I see this function used is

libgui/src/m-editor/file-editor-tab.cc:535:              add_octave_apis
(F__keywords__ ());       // add new entries

I changed this to Fiskeyword () and the code compiles fine, although I
still don't get properties/endproperties as keywords in the built-in editor.

--Rik