Change cvar from 'cv_' to 'dz_'

src/features/misc.c

@@ -14,7 +14,7 @@ void custom_crosshair(void) {
     int my = game_info->m_height / 2;
 
     /* The real length is sqrt(2 * (len^2)) */
-    const int len   = cv_crosshair->value;
+    const int len   = dz_crosshair->value;
     const int gap   = 1;
     const float w   = 1;
     const rgb_t col = { 255, 255, 255 };