Document cvc5-style numerals

This documents the addition of cvc5-style numerals.

spec/changelog.tex

@@ -33,7 +33,12 @@ Breaking changes:
         only determined by its syntactic category.
   \item The arguments for \proofRule{forall_inst} have been changed to
         no longer take the shape of bindings using \texttt{(:= x c)}.
-        Instead, the list of instatiation terms must follow the variable order and cover all the respective bound variables.
+        Instead, the list of instatiation terms must follow the variable
+        order and cover all the respective bound variables.
+  \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