reword a line from the help about mixed terrains

data/core/help.cfg

@@ -541,7 +541,7 @@ You can see what type of behavior the mixed terrain gives by mousing over its he
 
 <header>text='Defense Caps'</header>" + _"
 
-Some units have <italic>text='defense caps'</italic> for a particular basic terrain type. These units suffer a penalty on mixed terrains with that type — their defense can't exceed any of the caps." + _"
+Some units have <italic>text='defense caps'</italic> for a particular basic terrain type. These units suffer a penalty on mixed terrains with that type — their defense can't exceed the cap." + _"
 
 For example, the <ref>text='Loyalist Cavalryman' dst='..unit_Cavalryman'</ref> has a defense rating of 30% on forests, and a defense cap for forests. Thus, on forested hills, he has a defense rating of 30% rather than 40%, because the mixed rating cannot exceed the cap." + _"