Update README.md

Author: mhovd

README.md

@@ -4,7 +4,7 @@
 [![Documentation](https://github.com/LAPKB/pharmsol/actions/workflows/docs.yml/badge.svg)](https://github.com/LAPKB/pharmsol/actions/workflows/docs.yml)
 ![crates.io](https://img.shields.io/crates/v/pharmsol.svg)
 
-Simulate PK/PD profiles using ODE and analytical models.
+Simulate PK/PD profiles using ordinary and stochastic differential equations, or analytical models.
 
 ## Example