[doc/developer] add changelog for release 20.0; minor updates

doc/developer/changes.tex

@@ -5,6 +5,11 @@
 This chapter summarizes the major changes in this documentation between each
 \framac release, from newest to oldest.
 
+\section*{20.0 Calcium}
+\begin{itemize}
+\item \textbf{Ptests}: Documentation of the new directive \texttt{MODULE}.
+\end{itemize}
+
 \section*{19.0 Potassium}
 \begin{itemize}
 \item \textbf{ACSL Extension}: Document new \texttt{status} flag for registration functions

doc/developer/introduction.tex

@@ -35,8 +35,8 @@ of the \framac development.
 language~\cite{caml}. Motivations for this choice are given in a \framac
 experience report~\cite{framac-experience}. However this guide \emph{does not}
 provide any introduction to this programming language: the World Wide Web
-already contains plenty resources for \caml developers (see for instance
-\url{http://caml.inria.fr/resources/doc/index.en.html}).
+already contains plenty of resources for \caml developers (see for instance
+\url{https://ocaml.org/}).
 
 \section{About this document}