Add bulletpoint for conciseness of the proposal goal section

proposal/goals.tex

@@ -4,4 +4,7 @@
   \item What's the goal of the thesis in a nutshell? (Probably: solve that problem/analyze the solution suggested by Eti \cite{testref}/compare potential solutions/\dots)
   \item Then go into detail. What are the specifics of what you are going to do? Explain intermediate goals.
   \item Explain optional goals.
+  \item This section should be \emph{concise}!
+  It is typically no more than half a page.
+  If you need to provide (a lot of) contextual information to explain a goal, it is better to put that information in section 1 or section 2 than in this section.
 \end{itemize}