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.