Update NUG link to Data Types in ch02.adoc

[larsbarring]

@bzah found a broken link to NUG in chapter 2.2 Data Types and located the correct link. With the recent enhancement of the text related to packing/unpacking (#374 and #456) this link even more relevant. Thanks Abel for spotting this!

Would you @bzah mind also updating the history (cf. history.adoc in the PR)

Associated pull request

#444

As the PR was created already on August 9, I believe it can be merged as soon as ready, i.e. without the cool down period.

[bzah]

Hi, thanks Lars for opening the issue.
I don't have anything else to add to the PR, can we merge this now ?

[JonathanGregory]

Thanks for opening the issue, @larsbarring, and thanks for finding and fixing the problem, Abel @bzah. Please could you add a line for this issue at the top of history.adoc? I think the format should be obvious from the existing entries. Once that is in place in your PR, we can merge it.

[bzah]

I read the issue too quickly and didn't catch that the history.adoc update was needed.
It's now done.

[JonathanGregory]

Thanks, @bzah and @larsbarring. I will merge it now.