Remove unused code

kitty/cocoa_window.m

@@ -8,25 +8,6 @@
 
 #include "data-types.h"
 #include <Cocoa/Cocoa.h>
-#include <AvailabilityMacros.h>
-
-#if (MAC_OS_X_VERSION_MAX_ALLOWED < 101200)
-#define NSWindowStyleMaskTitled NSTitledWindowMask 
-#endif
-
-PyObject*
-cocoa_hide_titlebar(PyObject UNUSED *self, PyObject *window_id) {
-    NSWindow *window = (NSWindow*)PyLong_AsVoidPtr(window_id);
-    
-    @try {
-        [window setStyleMask:
-            [window styleMask] & ~NSWindowStyleMaskTitled];
-    } @catch (NSException *e) {
-        return PyErr_Format(PyExc_ValueError, "Failed to set style mask: %s: %s", [[e name] UTF8String], [[e reason] UTF8String]);
-    }
-    Py_RETURN_NONE;
-}
-
 
 PyObject*
 cocoa_get_lang(PyObject UNUSED *self) {