chore from属性添加更加详细的注释

ruoyi-common/ruoyi-common-mail/src/main/java/org/dromara/common/mail/config/properties/MailProperties.java

@@ -43,7 +43,13 @@ public class MailProperties {
     private String pass;
 
     /**
-     * 发送方，遵循RFC-822标准
+     * 发送方，遵循RFC-822标准<br>
+     * 发件人可以是以下形式：
+     *
+     * <pre>
+     * 1. user@xxx.xx
+     * 2.  name &lt;user@xxx.xx&gt;
+     * </pre>
      */
     private String from;