docs: add Size as an option for pageSize in docs for printToPDF (#15519)

docs/api/web-contents.md

@@ -1106,7 +1106,7 @@ Use `page-break-before: always; ` CSS style to force to print to a new page.
 * `options` Object
   * `marginsType` Integer (optional) - Specifies the type of margins to use. Uses 0 for
     default margin, 1 for no margin, and 2 for minimum margin.
-  * `pageSize` String (optional) - Specify page size of the generated PDF. Can be `A3`,
+  * `pageSize` String | Size (optional) - Specify page size of the generated PDF. Can be `A3`,
     `A4`, `A5`, `Legal`, `Letter`, `Tabloid` or an Object containing `height`
     and `width` in microns.
   * `printBackground` Boolean (optional) - Whether to print CSS backgrounds.

docs/api/webview-tag.md

@@ -526,7 +526,7 @@ Prints `webview`'s web page. Same as `webContents.print([options])`.
 * `options` Object
   * `marginsType` Integer (optional) - Specifies the type of margins to use. Uses 0 for
     default margin, 1 for no margin, and 2 for minimum margin.
-  * `pageSize` String (optional) - Specify page size of the generated PDF. Can be `A3`,
+  * `pageSize` String | Size (optional) - Specify page size of the generated PDF. Can be `A3`,
     `A4`, `A5`, `Legal`, `Letter`, `Tabloid` or an Object containing `height`
     and `width` in microns.
   * `printBackground` Boolean (optional) - Whether to print CSS backgrounds.