Updated the ChangeLog.

Author: gunterkoenigsmann

ChangeLog

@@ -2,6 +2,7 @@ Current:
   * Corrected a Regression: The better display of exponents failed for exp(x^2).
   * Seems like some Windows computers only have a numpad enter key.
   * Chinese translation updates from liulitchi.
+  * Russian translation updates from OlesyaGerasimenko.
 
 19.09.1:
   * The names of greek letters are no more converted to greek letters in variable