Fix description of 'core:version' and creation of short-descriptions

[bbc131]

Problem
The short description is generated by truncating the long description at the first period (".").
This doesn't work (for example) for the description of version in the global object, which contains the format specifier "X.Y.Z", the corresponding output is broken (ends with "X").

Fix
With the present commit, the first period followed by a space is used to truncate the short description.
Additionally, a missing period at the end of the description of version is added.

[Teque5]

Thanks! Seems like a no-nonsense PR, but I don't know where the short description is used so I'll let @777arc approve & merge.

[bbc131]

Alright, the short description is used for the tables.

[777arc]

Nice catch, and ty for the fix!

[777arc]

@bbc131 btw in case you didnt know, you can preview the html and pdf if you go to the github action that runs as part of the PR check, then go to summary and there should be a download at the bottom