15.0/relnotes: Mention mandoc update

[ziaee]

+ use commas to separate gitrefs. I can do the rest of page if good?
+ gitrefs are reverse chronological. ok?

[olce]

In D54013#1234041, @ziaee wrote:

+ use commas to separate gitrefs. I can do the rest of page if good?

Not too sure what the canonical format would be. Looking at 13.0, commas seem to be canonical, whereas not in 14.0. But the "Sponsored by:" thing I did was from 13.0 and looks better, and overall 13.0 seems to be a better model to copy. Personally, I support commas as well.

+ gitrefs are reverse chronological. ok?

For these, I would prefer chronological order. I think I've tried to respect that in most changes I did (but probably not all), but it's really not the end of the world if some are not. I don't remember checking older release notes about what they were doing. I've just checked on two random examples on 13.0's, and the order was chronological order in both cases, FWIW.

[olce]

As said in the previous comment, sorting commits by chronological order could be better.

[ziaee]

Thank you, I will use chronological order!