ts/wf/testcases [DOC]: mention reverse cases too

src/ts/wf/testcases/Makefile.crosscorrelation

@@ -12,10 +12,10 @@
 #
 # provided targets:
 #
-# cross_files_box.ps cross_box.ps
-# cross_files_sin3.ps cross_sin3.ps
-# cross_files_delta.ps cross_delta.ps
-# cross_files_noise.ps cross_noise.ps
+# cross_files_box.ps cross_box.ps cross_boxrev.ps
+# cross_files_sin3.ps cross_sin3.ps cross_sin3rev.ps
+# cross_files_delta.ps cross_delta.ps cross_deltarev.ps
+# cross_files_noise.ps cross_noise.ps cross_noiserev.ps
 #
 FILETYPE=ascii