Update rustfmt submodule

Amanieu · Amanieu · commit 794acd704719 · 2018-06-23T18:54:42.000+01:00
diff --git a/src/tools/rustfmt b/src/tools/rustfmt
@@ -1 +1 @@
-Subproject commit 08da30d72c9abfff4d41f6f081e31fd2929b820d
+Subproject commit 87edd75ecf26c9084969f431bb5e363693a8a4ca
