docs:add page header

docs/guide/option.md

@@ -5,7 +5,7 @@
 ```javascript
 import Editor from "@hufe921/canvas-editor"
 
-new Editor(container, [], {
+new Editor(container, IEditorData | IElement[], {
   // 配置项
 })
 ```
@@ -49,6 +49,7 @@ interface IEditorOption {
   headerTop?: number; // 页眉距离上边距。默认：50
   header?: IHeader; // 页眉信息。{data:string; color?:string; size?:number; font?:string;}
   paperDirection?: PaperDirection; // 纸张方向：纵向、横向
+  inactiveAlpha?: number; // 正文内容失焦时透明度。默认值：0.6
   watermark?: IWatermark; // 水印信息。{data:string; color?:string; opacity?:number; size?:number; font?:string;}
   control?: IControlOption; // 控件信息。 {placeholderColor?:string; bracketColor?:string; prefix?:string; postfix?:string;}
   checkbox?: ICheckboxOption; // 复选框信息。{width?:number; height?:number; gap?:number; lineWidth?:number; fillStyle?:string; fontStyle?: string;}