go-fuzz-dep: use a type alias for Bool

No practical consequences,
but this seems more semantically accurate.
It is intended to be a bool, not a named bool.

go-fuzz-dep/main.go

@@ -18,7 +18,7 @@ import (
 // Bool is just a bool.
 // It is used by code autogenerated by go-fuzz-build
 // to avoid compilation errors when a user's code shadows the built-in bool.
-type Bool bool
+type Bool = bool
 
 var (
 	inFD  FD