Hi everyone,

Prompted by [1], I started to work (slowly!) on a revision to the Widget
Manual.

My goals were to make it descriptive, well-organized, comprehensive, and
up-to date.  I also tried to preserve as much text as I could, although
I have the feeling that from the diff it might not look like that.

I added descriptions for the widget creation mechanism and added
mentions to the inheritance mechanism and completion mechanism, for
example.  I couldn't find the words to describe the :inline widgets
(there's a FIXME there).

I felt like it wasn't well-organized, so I rearranged some chapters.
Previously, commands and user options were described in various places,
and I tried to put them under common chapters.  I moved the default
widget description to be the very first one documented, so all
properties and default behavior can be described up-front.

To be comprehensive, I tried to cover all the properties that I felt
made sense, and with those descriptions I feel like the programmer
reading the library can acquire a better sense of how to use the
library.  I would like to add examples for the creation of widgets, and
my plan is to do that eventually.

And well, to be up-to-date it doesn't need much description from me.  I
added a lot of widgets that were previously undocumented, although I
did left out some that didn't seem to me like important enough (like the
insert-button, delete-button).  I did add mentions to those widgets, so
I think the curious reader can go on and inspect those widgets with the
Widget Browser.

At this point, I feel comfortable to share what I've done so far, so
that I can get some feedback.  Please help me by fixing my English,
recommending some cross-references, and of course, reviewing in general.
I hope this version is good enough for a first draft, and I'll
appreciate any comments I receive.

TIA,
Mauro.

[1]: https://lists.gnu.org/archive/html/emacs-devel/2023-07/msg00306.html