Update advice for conditional (ternary) operator

- Be more explicit about what is considered obvious.
- Make the point of not nesting them more prominent.

Author: amadio

talk/basicconcepts/control.tex

@@ -62,10 +62,11 @@
     \end{cppcode*}
   \end{exampleblock}
   \pause
-  \begin{alertblock}{Do not abuse}
+  \begin{alertblock}{Do not abuse it}
     \begin{itemize}
-      \item explicit ifs are easier to read \\
-      \item use only when obvious and not nested
+      \item Explicit \mintinline{cpp}{if}s are generally easier to read
+      \item Use the ternary operator with short conditions and expressions
+      \item Avoid nesting
     \end{itemize}
   \end{alertblock}
 \end{frame}