[Calculus] Fix conclusion of not_ite2

spec/rule_list.tex

@@ -915,7 +915,7 @@ with $1 \leq k \leq n$.
 \begin{plContainer}
 \begin{plList}
 \proofsep& i.& \neg(\operatorname{ite}\varphi_1\;\varphi_2\;\varphi_3) &(\dots)\\
-\proofsep& j.& \neg\varphi_2 , \neg\varphi_2 &(\currule; i)\\
+\proofsep& j.& \neg\varphi_1 , \neg\varphi_2 &(\currule; i)\\
 \end{plList}
 \end{plContainer}
 \end{proof-rule}