Document the valid range of tile coordinates in TileMapLayer

doc/classes/TileMap.xml

@@ -7,6 +7,7 @@
 		Node for 2D tile-based maps. Tilemaps use a [TileSet] which contain a list of tiles which are used to create grid-based maps. A TileMap may have several layers, layouting tiles on top of each other.
 		For performance reasons, all TileMap updates are batched at the end of a frame. Notably, this means that scene tiles from a [TileSetScenesCollectionSource] may be initialized after their parent. This is only queued when inside the scene tree.
 		To force an update earlier on, call [method update_internals].
+		[b]Note:[/b] For performance and compatibility reasons, the coordinates serialized by [TileMap] are limited to 16-bit signed integers, i.e. the range for X and Y coordinates is from [code]-32768[/code] to [code]32767[/code]. When saving tile data, tiles outside this range are wrapped.
 	</description>
 	<tutorials>
 		<link title="Using Tilemaps">$DOCS_URL/tutorials/2d/using_tilemaps.html</link>

doc/classes/TileMapLayer.xml

@@ -7,6 +7,7 @@
 		Node for 2D tile-based maps. A [TileMapLayer] uses a [TileSet] which contain a list of tiles which are used to create grid-based maps. Unlike the [TileMap] node, which is deprecated, [TileMapLayer] has only one layer of tiles. You can use several [TileMapLayer] to achieve the same result as a [TileMap] node.
 		For performance reasons, all TileMap updates are batched at the end of a frame. Notably, this means that scene tiles from a [TileSetScenesCollectionSource] may be initialized after their parent. This is only queued when inside the scene tree.
 		To force an update earlier on, call [method update_internals].
+		[b]Note:[/b] For performance and compatibility reasons, the coordinates serialized by [TileMapLayer] are limited to 16-bit signed integers, i.e. the range for X and Y coordinates is from [code]-32768[/code] to [code]32767[/code]. When saving tile data, tiles outside this range are wrapped.
 	</description>
 	<tutorials>
 		<link title="Using Tilemaps">$DOCS_URL/tutorials/2d/using_tilemaps.html</link>