Enhance SMS warning for two-factor authentication (#57555)

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: theodoracheng

data/reusables/two_fa/sms-warning.md

@@ -1,4 +1,4 @@
 Before using this method, be sure that you can receive text messages. Carrier rates may apply.
 
 > [!WARNING]
-> We **strongly recommend** using a TOTP application for two-factor authentication instead of SMS, and security keys as backup methods instead of SMS. {% data variables.product.github %} doesn't support sending SMS messages to phones in every country. Before configuring authentication via text message, review the list of countries where {% data variables.product.github %} supports authentication via SMS. For more information, see [AUTOTITLE](/authentication/securing-your-account-with-two-factor-authentication-2fa/countries-where-sms-authentication-is-supported).
+> We **strongly recommend** using a TOTP application for two-factor authentication instead of SMS, and using security keys as backup methods instead of SMS. SMS is susceptible to interception, does not provide resistance against phishing attacks, has unreliable deliverability, and is not supported in all countries. Before configuring authentication via text message, review the list of countries where {% data variables.product.github %} supports authentication via SMS. For more information, see [AUTOTITLE](/authentication/securing-your-account-with-two-factor-authentication-2fa/countries-where-sms-authentication-is-supported).