Adding spacing block supports to spacer block (#43366)

Author: ramonjd

docs/reference-guides/core-blocks.md

@@ -770,7 +770,7 @@ Add white space between blocks and customize its height. ([Source](https://githu
 
 -	**Name:** core/spacer
 -	**Category:** design
--	**Supports:** anchor
+-	**Supports:** anchor, spacing (margin)
 -	**Attributes:** height, width
 
 ## Table

packages/block-library/src/spacer/block.json

@@ -17,7 +17,13 @@
 	},
 	"usesContext": [ "orientation" ],
 	"supports": {
-		"anchor": true
+		"anchor": true,
+		"spacing": {
+			"margin": [ "top", "bottom" ],
+			"__experimentalDefaultControls": {
+				"margin": true
+			}
+		}
 	},
 	"editorStyle": "wp-block-spacer-editor",
 	"style": "wp-block-spacer"