[add] header/footer params for the export object of the pdf() method

Author: mafanya23

docs/chart/api/export/chart_pdf_method.md

@@ -39,6 +39,8 @@ description: You can explore the pdf method of Chart in the documentation of the
             - `title` - (optional) document name
             - `pageNumber` - (optional) current page number
             - `totalPages` - (optional) total pages in the document
+    - `header?: string` - (optional) an HTML template for the header in the exported file
+    - `footer?: string` - (optional) an HTML template for the footer in the exported file
 
 
 @example:
@@ -78,7 +80,8 @@ It is necessary to set sufficient margin for correct display of `headerTemplate`
 **Related API:** [exportStyles](chart/api/chart_exportstyles_config.md)
 
 **Change log:** 
+- The **header** and **footer** options of the export object were added in v8.4
 - The **theme**, **exportStyles** options of the export object were added in v8.1
-- The **pageRanges**, **displayHeaderFooter**, **footerTemplate**, **headerTemplate** options of the pdf object were added in 8.1
-- The method was added in v8.0
+- The **pageRanges**, **displayHeaderFooter**, **footerTemplate**, **headerTemplate** options of the pdf object were added in v8.1
+- Added in v8.0
 

docs/grid/api/export/grid_pdf_method.md

@@ -40,6 +40,8 @@ description: You can explore the pdf export method of Grid in the documentation
             - `title` - (optional) document name
             - `pageNumber` - (optional) current page number
             - `totalPages` - (optional) total pages in the document
+    - `header?: string` - (optional) an HTML template for the header in the exported file
+    - `footer?: string` - (optional) an HTML template for the footer in the exported file
 
 
 @example:
@@ -88,4 +90,6 @@ If you use Grid in conjunction with [Pagination](pagination.md), only the displa
 
 **Related API:** [exportStyles](grid/api/grid_exportstyles_config.md)
 
-**Change log:** Added in v8.1
+**Change log:** 
+- The **header** and **footer** options of the export object were added in v8.4
+- Added in v8.1

docs/treegrid/api/export/treegrid_pdf_method.md

@@ -40,7 +40,8 @@ description: You can explore the pdf export method of TreeGrid in the documentat
             - `title` - (optional) document name
             - `pageNumber` - (optional) current page number
             - `totalPages` - (optional) total pages in the document
-
+    - `header?: string` - (optional) an HTML template for the header in the exported file
+    - `footer?: string` - (optional) an HTML template for the footer in the exported file
 
 @example:
 // default export
@@ -88,4 +89,6 @@ If you use TreeGrid in conjunction with [Pagination](pagination.md), only the di
 
 **Related API:** [exportStyles](treegrid/api/treegrid_exportstyles_config.md)
 
-**Change log:** Added in v8.1
+**Change log:** 
+- The **header** and **footer** options of the export object were added in v8.4
+- Added in v8.1