feat: add optional emoji set address to emoji tags (#2247)

30.md

@@ -9,13 +9,14 @@ Custom Emoji
 Custom emoji may be added to **kind 0**, **kind 1**, **kind 7** ([NIP-25](25.md)) and **kind 30315** ([NIP-38](38.md)) events by including one or more `"emoji"` tags, in the form:
 
 ```
-["emoji", <shortcode>, <image-url>]
+["emoji", <shortcode>, <image-url>, <emoji-set-address>]
 ```
 
 Where:
 
 - `<shortcode>` is a name given for the emoji, which MUST be comprised of only alphanumeric characters and underscores.
 - `<image-url>` is a URL to the corresponding image file of the emoji.
+- `<emoji-set-address>` is an optional address pointer (`kind:pubkey:d-tag`) to the kind 30030 emoji set ([NIP-51](51.md)) the emoji belongs to.
 
 For each emoji tag, clients should parse emoji shortcodes (aka "emojify") like `:shortcode:` in the event to display custom emoji.
 
@@ -46,7 +47,7 @@ In kind 1 events, the `content` should be emojified.
   "kind": 1,
   "content": "Hello :gleasonator: 😂 :ablobcatrainbow: :disputed: yolo",
     "tags": [
-    ["emoji", "ablobcatrainbow", "https://gleasonator.com/emoji/blobcat/ablobcatrainbow.png"],
+    ["emoji", "ablobcatrainbow", "https://gleasonator.com/emoji/blobcat/ablobcatrainbow.png", "30030:79c2cae114ea28a981e7559b4fe7854a473521a8d22a66bbab9fa248eb820ff6:blobcats"],
     ["emoji", "disputed", "https://gleasonator.com/emoji/Fun/disputed.png"],
     ["emoji", "gleasonator", "https://gleasonator.com/emoji/Gleasonator/gleasonator.png"]
   ],