patch 8.0.0724: the message for yanking doesn't indicate the register

Problem:    The message for yanking doesn't indicate the register.
Solution:   Show the register name in the "N lines yanked" message. (Lemonboy,
            closes #1803, closes #1809)
diff --git a/src/testdir/Make_all.mak b/src/testdir/Make_all.mak
index 217a295..1606881 100644
--- a/src/testdir/Make_all.mak
+++ b/src/testdir/Make_all.mak
@@ -184,6 +184,7 @@
 	    test_quickfix.res \
 	    test_quotestar.res \
 	    test_retab.res \
+	    test_registers.res \
 	    test_ruby.res \
 	    test_search.res \
 	    test_signs.res \