doc: 增加文档

Author: ArgoZhang

src/BootstrapBlazor.Server/Components/Samples/Watermarks.razor

@@ -7,6 +7,9 @@
 
 <DemoBlock Title="@Localizer["WatermarkNormalTitle"]" Introduction="@Localizer["WatermarkNormalIntro"]" Name="Normal">
     <section ignore>
+        @((MarkupString)Localizer["WatermarkDescription"].Value)
+        <Pre>&lt;Layout&gt;&lt;/Layout&gt;
+&lt;Watermark IsPage="true" Text="BootstrapBlazor" FontSize="20" Color="#ddd" Rotate="-45" Gap="40"&gt;&lt;/Watermark&gt;</Pre>
         <div class="row form-inline g-3">
             <div class="col-12 col-sm-6">
                 <BootstrapInputGroup>

src/BootstrapBlazor.Server/Locales/en-US.json

@@ -7017,7 +7017,8 @@
     "WatermarkTitle": "Watermark",
     "WatermarkIntro": "Add specific text or patterns to the page",
     "WatermarkNormalTitle": "Basic usage",
-    "WatermarkNormalIntro": "Use the <code>Text</code> property to set a string to specify the watermark text"
+    "WatermarkNormalIntro": "Use the <code>Text</code> property to set a string to specify the watermark text",
+    "WatermarkDescription": "<p>How to add a watermark globally</p><p>You can add a watermark component to the template page <code>MainLayout</code> and set <code>IsPage=\"true\"</code></p>"
   },
   "BootstrapBlazor.Server.Data.AttributeItem": {
     "Name": "Name",

src/BootstrapBlazor.Server/Locales/zh-CN.json

@@ -7017,7 +7017,8 @@
     "WatermarkTitle": "Watermark 水印组件",
     "WatermarkIntro": "在页面上添加文本或图片等水印信息",
     "WatermarkNormalTitle": "基础用法",
-    "WatermarkNormalIntro": "使用 <code>Text</code> 属性设置一个字符串指定水印内容"
+    "WatermarkNormalIntro": "使用 <code>Text</code> 属性设置一个字符串指定水印内容",
+    "WatermarkDescription": "<p>全局增加水印实现方法</p><p>可以在模板页 <code>MainLayout</code> 中加水印组件并设置 <code>IsPage=\"true\"</code> 即可</p>"
   },
   "BootstrapBlazor.Server.Data.AttributeItem": {
     "Name": "参数",