Label name fix.

Doc/lib/libdecimal.tex

@@ -425,7 +425,7 @@ also have a number of specialized methods:
 
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%            
-\subsection{Context objects \label{decimal-decimal}}
+\subsection{Context objects \label{decimal-context}}
 
 Contexts are environments for arithmetic operations.  They govern precision,
 set rules for rounding, determine which signals are treated as exceptions, and