How i can i add open login plugin button to notices in a way that we have Please " Login with twitter , log in or register"
This is only possibly with a core hack. You need to modify the function qa_insert_login_links from qa-app-format.php, which is in the core of Q2A and cannot be overridden by a plugin.
Have a look at this function here: https://github.com/q2a/question2answer/blob/master/qa-include/qa-app-format.php#L1018
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