repl: Fix value printing corruption

The resume call would get some non-flushed(?) data.
Extending the pause to include the newline makes the complete flush
part of the pause.

(cherry picked from commit 880489051a)

src/libcmd/repl.cc

@@ -694,8 +694,10 @@ ProcessLineResult NixRepl::processLine(std::string line)
         } else {
             Value v;
             evalString(line, v);
+            logger->pause();
             printValue(std::cout, v, 1);
             std::cout << std::endl;
+            logger->resume();
         }
     }