Upgrade rust/crates/proc-macro-nested to 0.1.6

* Keep local changes:
  * src/lib.rs (include out/count.rs)
  * out/count.rs (copied from new cargo build)

Test: make
Change-Id: I83865b32b0675023e29da3fb62207cebe42f487b
diff --git a/METADATA b/METADATA
index 1bef54b..a328cee 100644
--- a/METADATA
+++ b/METADATA
@@ -1,7 +1,5 @@
 name: "proc-macro-nested"
-description:
-    "Support for nested proc-macro-hack invocations"
-
+description: "Support for nested proc-macro-hack invocations"
 third_party {
   url {
     type: HOMEPAGE
@@ -11,7 +9,11 @@
     type: GIT
     value: "https://github.com/dtolnay/proc-macro-hack"
   }
-  version: "0.1.4"
-  last_upgrade_date { year: 2020 month: 3 day: 17 }
+  version: "0.1.6"
   license_type: NOTICE
+  last_upgrade_date {
+    year: 2020
+    month: 7
+    day: 10
+  }
 }