fixes native user snippet (#12875)

Author: kahest

platform-includes/enriching-events/set-user/native.mdx

@@ -2,7 +2,7 @@
 #include <sentry.h>
 
 sentry_value_t user = sentry_value_new_object();
-sentry_value_set_by_key(user, "ip_address", sentry_value_new_string("\{\{auto}}"));
+sentry_value_set_by_key(user, "ip_address", sentry_value_new_string("{{auto}}"));
 sentry_value_set_by_key(user, "email", sentry_value_new_string("jane.doe@example.com"));
 sentry_set_user(user);
 ```