update the rustfmt submodule

Jorge Aparicio · Jorge Aparicio · commit 98689c505739 · 2017-04-07T00:00:03.000Z
diff --git a/rustfmt b/rustfmt
@@ -1 +1 @@
-Subproject commit b3a4ba570e8e5066564c2e9a96cc381a443d544f
+Subproject commit b46c147fedd5c744f63c6941de75e738e6c5047b
