Fix typo (#4249)

Modelica/Mechanics/Translational/Components/ElastoGap.mo

@@ -119,7 +119,7 @@ Note, since |f_d| ≤ |f_c|, pulling forces cannot occur and the cont
 is always continuous, especially around the start of the penetration at s_rel = s_rel0.
 On the contrary, this leads to the contact force <code>f&nbsp;=&nbsp;0</code> even if
 <code>contact&nbsp;= true</code> is still indicated around the end of the penetration.
-This is because <code>contact</code> indicates only the occurance of geometry penetration.
+This is because <code>contact</code> indicates only the occurrence of geometry penetration.
 </p>
 
 <p>