fix typo

Electrostatics/microstrip.geo

@@ -21,7 +21,7 @@ p0 = h / 10. * s ;
 pLine0 = w/2. / 10. * s ;  pLine1 = w/2. / 50. * s ;
 pxBox = xBox / 10. * s ;  pyBox = yBox / 8. * s ;
 
-/* Definition of gemetrical points */
+/* Definition of geometrical points */
 
 Point(1) = { 0   , 0, 0, p0} ;
 Point(2) = { xBox, 0, 0, pxBox} ;