feat: Add a notice about email to the first-run banner

src/service/firstrun/mod.rs

@@ -228,19 +228,29 @@ impl Service {
 				);
 			},
 		}
+
+		if self.services.config.suspend_on_register {
+			eprintln!(
+				"{} Accounts created after yours will be suspended, as set in your configuration.",
+				"Your account will not be suspended when you register.".green()
+			);
+		}
+
+		if let Some(smtp) = &self.services.config.smtp {
+			if smtp.require_email_for_registration || smtp.require_email_for_token_registration {
+				eprintln!(
+					"{} Accounts created after yours may be required to provide an email address, as set in your configuration.",
+					"You will not be asked for your email address when you register.".yellow(),
+				);
+			}
+			eprintln!("If you wish to associate an email address with your account, you may do so after registration in your client's settings (if supported).");
+		}
+
 		eprintln!(
 			"{} https://matrix.org/ecosystem/clients/",
 			"Find a list of Matrix clients here:".bold()
 		);
 
-		if self.services.config.suspend_on_register {
-			eprintln!(
-				"{} Because you enabled suspend-on-register in your configuration, accounts \
-				 created after yours will be automatically suspended.",
-				"Your account will not be suspended when you register.".green()
-			);
-		}
-
 		if self
 			.services
 			.config