fixed typing rule miss

src/typing.tex

@@ -11,8 +11,8 @@
   \begin{minipage}[t]{0.5\hsize}
   \centering
      \begin{equation*}
-       \frac{ \Gamma \vdash e_1:N \quad \Gamma \vdash e_2:\tau }{\Gamma \vdash delay\ e_1\ e_2 : \tau}
+      \frac{ \Gamma \vdash n:N \quad \Gamma \vdash e1:\tau\quad \Gamma \vdash e_2:R }{\Gamma \vdash delay\, n\, e_1\, e_2 : \tau}
-     \end{equation*}\textrm{T-DELAY}
+     \end{equation*}\textrm{[T-DELAY]}
   \end{minipage}\\
   
   \begin{minipage}[t]{0.4\hsize}