[clang-tidy] use override instead of virtual

Found with modernize-use-override

Signed-off-by: Rosen Penev <rosenp@gmail.com>

src/input/plugins/SmbclientInputPlugin.cxx

@@ -43,7 +43,7 @@ public:
 		SetReady();
 	}
 
-	~SmbclientInputStream() {
+	~SmbclientInputStream() override {
 		const std::lock_guard<Mutex> lock(smbclient_mutex);
 		smbc_close(fd);
 		smbc_free_context(ctx, 1);