fixing whitespace in contracts.cpp

Author: Remi Delmas

src/goto-instrument/contracts/contracts.cpp

@@ -1652,7 +1652,7 @@ bool code_contractst::is_loop_free(const goto_programt &goto_program)
     goto_program.instructions.size() == cfg.size(),
     "Instruction list vs CFG size mismatch.");
 
-  //compute SCCs
+  // compute SCCs
   std::vector<node_indext> node_to_scc(cfg.size(), -1);
   auto nof_sccs = cfg.SCCs(node_to_scc);