[MRG] Locality Sensitive Hashing for approximate nearest neighbor search(GSoC)

You're not pointing to the object (class) that does the work in scikit-learn. You need to refer to it. Remember: this is the documentation of a software package.

In general, your documentation starts bit too much with general considerations. It reads like a maths course on ANNs. The goal of the documentation is to give quickly indications on how to solve concrete problems.