Add changes to changelog

spec/changelog.tex

@@ -27,6 +27,10 @@ Breaking changes:
   \item The rules \proofRule{and_pos}, \proofRule{or_neg}, \proofRule{and},
         \proofRule{not_or} now have one argument that indicates which subterm
         they use.
+  \item Add new syntax for decimal and negative numbers and use it
+        for \proofRule{la_generic}.
+  \item Restrict sorting of numbers such that the sort of a constant is
+        only determined by its syntactic category.
 \end{itemize}
 
 \noindent