Fix how the rule is displayed in the error message.

Bug: 204001941
Test: internal
Change-Id: I19c73356cc305ec7a6dfd3bddbde775ef9ca4953
diff --git a/mk2rbc/mk2rbc_test.go b/mk2rbc/mk2rbc_test.go
index b657e76..d3ac7fc 100644
--- a/mk2rbc/mk2rbc_test.go
+++ b/mk2rbc/mk2rbc_test.go
@@ -963,6 +963,23 @@
   rblf.inherit(handle, _varmod, _varmod_init)
 `,
 	},
+	{
+		desc:   "Ignore make rules",
+		mkname: "product.mk",
+		in: `
+foo: foo.c
+	gcc -o $@ $*`,
+		expected: `# MK2RBC TRANSLATION ERROR: unsupported line rule:       foo: foo.c
+#gcc -o $@ $*
+# rule:       foo: foo.c
+# gcc -o $@ $*
+load("//build/make/core:product_config.rbc", "rblf")
+
+def init(g, handle):
+  cfg = rblf.cfg(handle)
+  rblf.warning("product.mk", "partially successful conversion")
+`,
+	},
 }
 
 var known_variables = []struct {