Update FileDialog filters documentation

doc/classes/DisplayServer.xml

@@ -136,6 +136,7 @@
 			<param index="6" name="callback" type="Callable" />
 			<description>
 				Displays OS native dialog for selecting files or directories in the file system.
+				Each filter string in the [param filters] array should be formatted like this: [code]*.txt,*.doc;Text Files[/code]. The description text of the filter is optional and can be omitted. See also [member FileDialog.filters].
 				Callbacks have the following arguments: [code]status: bool, selected_paths: PackedStringArray, selected_filter_index: int[/code].
 				[b]Note:[/b] This method is implemented if the display server has the [constant FEATURE_NATIVE_DIALOG] feature. Supported platforms include Linux (X11/Wayland), Windows, and macOS.
 				[b]Note:[/b] [param current_directory] might be ignored.
@@ -157,6 +158,7 @@
 			<param index="8" name="callback" type="Callable" />
 			<description>
 				Displays OS native dialog for selecting files or directories in the file system with additional user selectable options.
+				Each filter string in the [param filters] array should be formatted like this: [code]*.txt,*.doc;Text Files[/code]. The description text of the filter is optional and can be omitted. See also [member FileDialog.filters].
 				[param options] is array of [Dictionary]s with the following keys:
 				- [code]"name"[/code] - option's name [String].
 				- [code]"values"[/code] - [PackedStringArray] of values. If empty, boolean option (check box) is used.

doc/classes/FileDialog.xml

@@ -131,7 +131,7 @@
 			The dialog's open or save mode, which affects the selection behavior. See [enum FileMode].
 		</member>
 		<member name="filters" type="PackedStringArray" setter="set_filters" getter="get_filters" default="PackedStringArray()">
-			The available file type filters. For example, this shows only [code].png[/code] and [code].gd[/code] files: [code]set_filters(PackedStringArray(["*.png ; PNG Images","*.gd ; GDScript Files"]))[/code]. Multiple file types can also be specified in a single filter. [code]"*.png, *.jpg, *.jpeg ; Supported Images"[/code] will show both PNG and JPEG files when selected.
+			The available file type filters. Each filter string in the array should be formatted like this: [code]*.txt,*.doc;Text Files[/code]. The description text of the filter is optional and can be omitted.
 		</member>
 		<member name="mode_overrides_title" type="bool" setter="set_mode_overrides_title" getter="is_mode_overriding_title" default="true">
 			If [code]true[/code], changing the [member file_mode] property will set the window title accordingly (e.g. setting [member file_mode] to [constant FILE_MODE_OPEN_FILE] will change the window title to "Open a File").