Fixed typo introduced in previous commit

git-svn-id: https://www.dynare.org/svn/dynare/trunk@2860 ac1d8469-bf42-47a9-8791-bf33cf982152

preprocessor/DynareBison.yy

@@ -1706,7 +1706,7 @@ symbol : NAME
        | ABAND {$$ = new string("aband");}
        | CMS {$$ = new string("cms");}
        | NCMS {$$ = new string("ncms");}
-       | CNUM {$$ = new string("cnmum");}
+       | CNUM {$$ = new string("cnum");}
        ;
 %%