patch 8.2.2889: typo and verbose comment in Makefiles

Problem:    Typo and verbose comment in Makefiles.
Solution:   Fix typo. Use @#. (Ken Takata, closes #8252)
diff --git a/src/testdir/Makefile b/src/testdir/Makefile
index 050a032..3f33bf8 100644
--- a/src/testdir/Makefile
+++ b/src/testdir/Makefile
@@ -40,7 +40,7 @@
 benchmark: $(SCRIPTS_BENCH)
 
 report:
-	# without the +eval feature test_result.log is a copy of test.log
+	@# without the +eval feature test_result.log is a copy of test.log
 	@/bin/sh -c "if test -f test.log; \
 		then cp test.log test_result.log; \
 		else echo No failures reported > test_result.log; \