Improve strings (#13548)

* Correct oauth signup title

When linking accounts, a password is not required anymore,
so this string becomes confusing

* string "remenber me": be more precise

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: techknowlogick <techknowlogick@gitea.io>

options/locale/locale_en-US.ini

@@ -245,7 +245,7 @@ register_helper_msg = Already have an account? Sign in now!
 social_register_helper_msg = Already have an account? Link it now!
 disable_register_prompt = Registration is disabled. Please contact your site administrator.
 disable_register_mail = Email confirmation for registration is disabled.
-remember_me = Remember Me
+remember_me = Remember this Device
 forgot_password_title= Forgot Password
 forgot_password = Forgot password?
 sign_up_now = Need an account? Register now.
@@ -278,7 +278,7 @@ twofa_scratch_token_incorrect = Your scratch code is incorrect.
 login_userpass = Sign In
 login_openid = OpenID
 oauth_signup_tab = Register New Account
-oauth_signup_title = Add Email and Password (for Account Recovery)
+oauth_signup_title = Complete New Account
 oauth_signup_submit = Complete Account
 oauth_signin_tab = Link to Existing Account
 oauth_signin_title = Sign In to Authorize Linked Account