Applications+DevTools+MenuApplets: Drop "unix" pledge when possible

Now that the "unix" pledge is no longer required for socket I/O, we can
drop it after making the connections we need in a program.

In most GUI program cases, once we've connected to the WindowServer by
instantiating a GApplication, we no longer need "unix" :^)

Applications/Help/main.cpp

@@ -31,7 +31,7 @@ int main(int argc, char* argv[])
 
     GApplication app(argc, argv);
 
-    if (pledge("stdio unix shared_buffer rpath", nullptr) < 0) {
+    if (pledge("stdio shared_buffer rpath", nullptr) < 0) {
         perror("pledge");
         return 1;
     }