Update git submodules

* Update prebuilts/rust from branch 'master'
  to 3cebe0166d7ae8445e80fecb3fb6985cbe9d5482
  - Make `rustfmt` available for other modules
    
    Using `cc_prebuilt_binary` works fine, it doesn’t actually care if the
    binary is written in C++ of Rust.
    
    Test: makes https://r.android.com/2094185 work
    Change-Id: I4d08a8fd7f3794e77aa34b8c5ade6aaf08d720a1
    
diff --git a/prebuilts/rust b/prebuilts/rust
index 29a5dc1..3cebe01 160000
--- a/prebuilts/rust
+++ b/prebuilts/rust
@@ -1 +1 @@
-Subproject commit 29a5dc1ff2cd848d686d705cb9f097cc7ab25089
+Subproject commit 3cebe0166d7ae8445e80fecb3fb6985cbe9d5482