update libcore's comment about str tests

ExpHP · ExpHP · commit 4fab1674c3db · 2018-04-30T07:36:56.000-04:00
diff --git a/src/libcore/tests/str.rs b/src/libcore/tests/str.rs
@@ -8,4 +8,4 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// All `str` tests live in collectionstests::str
+// All `str` tests live in liballoc/tests
