Bump rustfmt to 1.4.16

Mark-Simulacrum · Mark-Simulacrum · commit 688c9bd03300 · 2020-06-12T10:04:35.000-04:00
This corrects a breaking change where `#[cfg_attr(rustfmt, rustfmt_skip)]`
stopped working in 1.44.0.
diff --git a/Cargo.lock b/Cargo.lock
@@ -4397,7 +4397,7 @@ dependencies = [
 
 [[package]]
 name = "rustfmt-nightly"
-version = "1.4.14"
+version = "1.4.16"
 dependencies = [
  "annotate-snippets",
  "bytecount",
diff --git a/src/tools/rustfmt b/src/tools/rustfmt
@@ -1 +1 @@
-Subproject commit e417356684a36ae9c8c4014e8f0cd86650e40dd2
+Subproject commit 939e164c29f92bdbffdb156fa3d53aabbe9a2e0b
