Add missing comma (#280)

src/content/1.2/types-and-functions.tex

@@ -24,7 +24,7 @@ \section{Who Needs Types?}
 remaining programs will have a better chance of being useful. Type
 checking provides yet another barrier against nonsensical programs.
 Moreover, whereas in a dynamically typed language, type mismatches would
-be discovered at runtime, in strongly typed statically checked languages
+be discovered at runtime, in strongly typed statically checked languages,
 type mismatches are discovered at compile time, eliminating lots of
 incorrect programs before they have a chance to run.
 
@@ -408,7 +408,7 @@ \section{Examples of Types}
 to define a Boolean type in C++ as an enumeration:
 
 \begin{snip}{cpp}
-enum bool { 
+enum bool {
     true,
     false
 };
@@ -468,7 +468,7 @@ \section{Challenges}
 \end{minted}
   \item
 \begin{minted}{cpp}
-bool f() { 
+bool f() {
     std::cout << "Hello!" << std::endl;
     return true;
 }
@@ -490,4 +490,4 @@ \section{Challenges}
   \code{Void}, \code{()} (unit), and \code{Bool}; with arrows
   corresponding to all possible functions between these types. Label the
   arrows with the names of the functions.
-\end{enumerate}
+\end{enumerate}