Add fold feature to syn crate.

cbindgen depends on syn:fold.

Bug: 370957658
Test: Built cbindgen + treehugger
Change-Id: I6a17f27ee54b4f47dfeb5126e72ae3f48268be9a
Merged-In: I6a17f27ee54b4f47dfeb5126e72ae3f48268be9a
diff --git a/crates/syn/Android.bp b/crates/syn/Android.bp
index b5c735e..74a5d3e 100644
--- a/crates/syn/Android.bp
+++ b/crates/syn/Android.bp
@@ -26,6 +26,7 @@
         "default",
         "derive",
         "extra-traits",
+        "fold",
         "full",
         "parsing",
         "printing",
diff --git a/crates/syn/cargo_embargo.json b/crates/syn/cargo_embargo.json
index 0863453..f1ed023 100644
--- a/crates/syn/cargo_embargo.json
+++ b/crates/syn/cargo_embargo.json
@@ -4,7 +4,8 @@
     "full",
     "visit",
     "visit-mut",
-    "extra-traits"
+    "extra-traits",
+    "fold"
   ],
   "package": {
     "syn": {