Style(AI):输入内容设置最多支持500字和最大高度，超过则出现Y轴滚动条

aiChat/components/bottomSend.vue

@@ -29,7 +29,7 @@
             :adjust-position="true"
             :auto-height="true"
             :disabled="loading"
-            :maxlength="-1"
+            :maxlength="500"
             class="inp"
             @confirm="sendHandle"
             @focus="promptInputFocusHandle"

assets/css/aiChat.less

@@ -182,11 +182,13 @@ page {
 					z-index: 5;
 					width: 100%;
 					height: 88rpx;
+					max-height: 220rpx;
 					border: 0;
 					box-sizing: border-box;
 					line-height: 48rpx;
 					color: #333;
 					font-size: 30rpx;
+					overflow-y: auto;
 				}
 				.placeholder-txt {
 					position: absolute;