doc/syntax.tex: Give cross-ref to (stub) metaclass section.

Fixes a fixme.

diff --git a/doc/syntax.tex b/doc/syntax.tex
index c6033cf3cd53fdcdb154e83b67a55c6cfd1d8c7c..50cea662178520da6ab048587c89a263e7db3bd1 100644 (file)
--- a/doc/syntax.tex
+++ b/doc/syntax.tex
@@ -593,7 +593,7 @@ properties are as follows.
   which messages it will respond to, and what its behaviour will be when it
   receives them.  The property value must be an identifier naming a defined
   subclass of @"SodClass".  The default metaclass is @"SodClass".
-  %%% FIXME xref to theory
+  See \xref{sec:concepts.metaclasses} for more details.
 \item[@"nick"] A nickname for the class, to be used to distinguish it from
   other classes in various limited contexts.  The property value must be an
   identifier; the default is constructed by forcing the class name to