Fix column layout in documentation of Modelica.Media.IdealGases.SingleGases (#4588)

Author: LeoSchmider

Modelica/Media/IdealGases/SingleGases.mo

@@ -363,7 +363,7 @@ Propane           1-Propanol       1-Butene       N-Butane         1-Pentene
 N-Pentane         Benzene          1-Hexene       N-Hexane         1-Heptane
 N-Heptane         Ethylbenzene     N-Octane       Chlorine         Fluorine
 Hydrogen          Steam            Helium         Ammonia          Nitric Oxide
-Nitrogen Dioxide  Nitrogen         Nitrous        Oxide            Neon Oxygen
+Nitrogen Dioxide  Nitrogen         Nitrous Oxide  Neon             Oxygen
 Sulfur Dioxide    Sulfur Trioxide
 </pre></blockquote>
 </html>"));