Computes the dot product of the two input vectors.

The dot product is algebraically defined as taking 2 vectors of the same length, and multiplying each number side-by-side, and them summing them all.

e.g. If vector 1 is [2,3,-2] and vector 2 is [1,2,3]:

• Multiplying 2 and 1 gives 2.
• Multiplying 3 and 2 gives 6.
• Multiplying -2 and 3 gives -6.
• Adding them all gives 2, the dot product of them two.