[defns.const.subexpr] Remove superfluous words

Author: cpplearner

source/lib-intro.tex

@@ -357,8 +357,7 @@
 an expression whose evaluation as subexpression of a
 \grammarterm{conditional-expression}
 \tcode{CE}~(\ref{expr.cond}) would not prevent \tcode{CE}
-from being a core constant expression~(\ref{expr.const}).
-\tcode{false}. \exitexample
+from being a core constant expression~(\ref{expr.const})
 
 \rSec1[defns.additional]{Additional definitions}