Minor fix in Degrees

Author: ulthiel

Source/MatrixGroups/Invariants.i.m

@@ -280,8 +280,8 @@ intrinsic Degrees(~G::GrpMat : UseDB:=true)
 intrinsic Degrees(G::GrpMat) -> SeqEnum
 {}
 
-    Degrees(~R);
-    return R`Degrees;
+    Degrees(~G);
+    return G`Degrees;
 
 end intrinsic;