Mention all new options in NEWS

[Michael Snyder]

Eli Zaretskii wrote:
> I was looking for the exact form of the disassemble-next-line option
> (I forgot its precise name), and found out that we don't have it
> listed in NEWS.
> 
> Would it be OK with everybody to request that new options be also
> mentioned in NEWS, in addition to new commands?  If others agree, I
> volunteer to document in NEWS all the options we added since GDB 6.8.

Sounds great, thanks for doing this.