Add back the default axes style documentation

[Andrew15-5]

Why did this disappear from the docs? In cetz v0.2.2 under 5.2.17 there was a list of default style for different axis styles. But now this information is gone. So I have to keep using that version of the manual to look up the needed settings.

To be completely honest, the documentation after the split became super confusing and lacking information that was previously available in the manual. Even if I try, for example, look for set-style in the new non-cetz-plot online documentation, it won't show anything useful (not for core cetz, nor for the plot library). Reading docs is literally the only way I can make the full use of cetz, otherwise I am stuck with what I can remember from reading the docs before. And that's not a lot.

[johannes-wolf]

I added back the previous documentation about axis styling with #100.

[Andrew15-5]

Thanks.