Add support for dot distance

[patcon]

Re-ticketed from #106 (comment)

Annoy already supports this, we just didn't. (though we erroneous allow it to be set when initializing PaCMAP on master rn)

Code written with advice of chatgpt (by giving it the annoy C code, and showing it what we did in pacmap for the other distances). It may have made an error, but it seemed reasonable to me: https://chatgpt.com/share/6866e591-6860-800b-aa9c-e46fc44b59c5

PR only opened for initial feedback. cc @mathematicalmichael

To Dos

• implement draft change
• write tests

[mathematicalmichael]

happy to put this through some production-like testing in pacmap-dev as a staging ground before un-drafting this (just ping me when its ready - this change seems ok from first glance). I've got a visual interface that will let me compare/share different embedding results on the same datasets. the use of this distance is uncharted waters afaik but in theory it should work just fine.

[patcon]

thanks! heh it's as good as it's getting from me, so test away :)