refactor: make savePath a property on DownloadItem (#18677)

docs/api/download-item.md

@@ -80,7 +80,9 @@ The `downloadItem` object has the following methods:
 
 The API is only available in session's `will-download` callback function.
 If user doesn't set the save path via the API, Electron will use the original
-routine to determine the save path(Usually prompts a save dialog).
+routine to determine the save path; this usually prompts a save dialog.
+
+**[Deprecated](modernization/property-updates.md): use the `savePath` property instead.**
 
 #### `downloadItem.getSavePath()`
 
@@ -88,6 +90,8 @@ Returns `String` - The save path of the download item. This will be either the p
 set via `downloadItem.setSavePath(path)` or the path selected from the shown
 save dialog.
 
+**[Deprecated](modernization/property-updates.md): use the `savePath` property instead.**
+
 #### `downloadItem.setSaveDialogOptions(options)`
 
 * `options` SaveDialogOptions - Set the save file dialog options. This object has the same
@@ -181,3 +185,13 @@ Returns `String` - ETag header value.
 
 Returns `Double` - Number of seconds since the UNIX epoch when the download was
 started.
+
+### Instance Properties
+
+#### `downloadItem.savePath`
+
+A `String` property that determines the save file path of the download item.
+
+The property is only available in session's `will-download` callback function.
+If user doesn't set the save path via the property, Electron will use the original
+routine to determine the save path; this usually prompts a save dialog.

docs/api/modernization/property-updates.md

@@ -20,9 +20,6 @@ The Electron team is currently undergoing an initiative to convert separate gett
   * `visibleOnAllWorkspaces`
 * `crashReporter` module
   * `uploadToServer`
-* `DownloadItem` class
-  * `savePath`
-  * `paused`
 * `Session` module
   * `preloads`
 * `webContents` module
@@ -47,6 +44,8 @@ The Electron team is currently undergoing an initiative to convert separate gett
   * `applicationMenu`
   * `badgeCount`
   * `name`
+* `DownloadItem` class
+  * `savePath`
 * `BrowserWindow` module
   * `autohideMenuBar`
   * `resizable`