Expand and correct documentation

coins/monero/generators/src/lib.rs

@@ -1,3 +1,7 @@
+//! Generators used by Monero in both its Pedersen commitments and Bulletproofs(+).
+//! An implementation of Monero's `ge_fromfe_frombytes_vartime`, simply called
+//! `hash_to_point` here, is included, as needed to generate generators.
+
 use lazy_static::lazy_static;
 
 use tiny_keccak::{Hasher, Keccak};