[RFA/doco] Add documentation for observer.[hc] (2nd version)

[Eli Zaretskii]

> Date: Mon, 10 Mar 2003 11:59:59 -0800
> From: Joel Brobecker <brobecker@gnat.com>
> 
> Here is a second shot at the observer documentation. Hopefully, I
> addressed all issues.

Thanks.  I still have a few comments.

> An observer is an entity who is interested in being notified when GDB

When you introduce a new term, such as "observer" in the above text,
it is best to put it into @dfn, like this:

 An @dfn{observer} is an entity who is interested in being notified when GDB

(btw, it should be "whcih", not "who").  This makes the term stand
out, and clearly shows to the reader what is the term you introduce.


> The entity being observed is called the Subject.

Same here:

  The entity being observed is called @dfn{the Subject}.

(Btw, is it really necessary to start "Subject" with a capital S?)

Please also make sure each sentence ends with either a newline or 2
spaces after the period.

Thanks!