custom: add Write.deinit and fix WildNoise.deinit

src/custom.zig

@@ -91,7 +91,7 @@ pub const WildNoise = struct {
         }
     }
 
-    pub fn deinit(self: *RandomNoise) void {
+    pub fn deinit(self: *WildNoise) void {
         if (self.allocator == null) return;
         if (self.rand_buf == null) return;
         self.allocator.?.free(self.rand_buf.?);
@@ -125,6 +125,8 @@ pub const Write = struct {
         };
     }
 
+    pub fn deinit(self: *Write) void {}
+
     pub fn run(self: *Write, bufs: *RunBuffers) void {
         bufs.out[0] = self.data;
     }