Remove redundant `struct` keys

Because this is C++ code, GCC 12 says things like:

    Socket.hpp:166:24: error:
    redundant class-key ‘struct’ in reference to ‘struct sockaddr_un’
    [-Werror=redundant-tags]

1 files changed, 1 insertions, 1 deletions

diff --git a/test/socket_test.cpp b/test/socket_test.cpp
index 964a8ae..da05c40 100644
--- a/test/socket_test.cpp
+++ b/test/socket_test.cpp
@@ -47,7 +47,7 @@ main()
     int status = 0;
     waitpid(child_pid, &status, 0);
 
-    struct pollfd pfds[2];
+    pollfd pfds[2];
     pfds[0].fd      = unix_server_sock.fd();
     pfds[0].events  = POLLIN;
     pfds[0].revents = 0;