Add XmlMessageHelper

mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/XML.kt

@@ -104,6 +104,29 @@ class XMLMessageBuilder(
     }
 }
 
+@MiraiExperimentalAPI
+object XmlMessageHelper {
+    fun share(u: String, title: String?, content: String?, image: String?) = buildXMLMessage {
+        templateId = 12345
+        serviceId = 1
+        action = "web"
+        brief = "[分享] " + (title ?: "")
+        url = u
+        item {
+            layout = 2
+            if (image != null) {
+                picture(image)
+            }
+            if (title != null) {
+                title(title)
+            }
+            if (content != null) {
+                summary(content)
+            }
+        }
+    }
+}
+
 @Target(AnnotationTarget.CLASS, AnnotationTarget.FUNCTION, AnnotationTarget.TYPE)
 @DslMarker
-annotation class XMLDsl
+annotation class XMLDsl