Make `rustfmt.toml` a symlink

Instead of making a copy of `soong/scripts/rustfmt.toml`, we now
reference it via a symlink. The content is unchanged.

Test: manual
Bug: 229825251
Change-Id: Ia0e833e6bcd97da01715a964b15255014b11ef6f
diff --git a/remote_provisioning/cert_validator/rustfmt.toml b/remote_provisioning/cert_validator/rustfmt.toml
deleted file mode 100644
index cefaa42..0000000
--- a/remote_provisioning/cert_validator/rustfmt.toml
+++ /dev/null
@@ -1,5 +0,0 @@
-# Android Format Style
-
-edition = "2021"
-use_small_heuristics = "Max"
-newline_style = "Unix"
diff --git a/remote_provisioning/cert_validator/rustfmt.toml b/remote_provisioning/cert_validator/rustfmt.toml
new file mode 120000
index 0000000..99fc71e
--- /dev/null
+++ b/remote_provisioning/cert_validator/rustfmt.toml
@@ -0,0 +1 @@
+../../../../build/soong/scripts/rustfmt.toml
\ No newline at end of file