28: Add missing semicolon in solution for Rust track exercise "Raindrops".

Created by  Aaw9nJhsNmfzFih9mKyNw9mV8CgERXJkRa1kK1Kx3LQH  on September 2, 2021
J3ZPU3R2JTPQF3KIKRWEQHEFD7ISDGP7QTEKRBQI3SWC6ALZT54QC
Change contents