nip54: fix json indentation.

54.md

@@ -13,11 +13,11 @@ Articles are identified by lowercase, normalized ascii `d` tags.
 ### Articles
 ```jsonc
 {
-   "content": "A wiki is a hypertext publication collaboratively edited and managed by its own audience.",
-   "tags": [
-       [ "d", "wiki" ],
-       [ "title", "Wiki" ],
-   ]
+  "content": "A wiki is a hypertext publication collaboratively edited and managed by its own audience.",
+  "tags": [
+    ["d", "wiki"],
+    ["title", "Wiki"],
+  ]
 }
 ```
 
@@ -93,14 +93,14 @@ Users can request other users to get their entries merged into someone else's en
 
 ```jsonc
 {
-   "content": "I added information about how to make hot ice-creams",
-   "kind": 818,
-   "tags": [
-       [ "a", "30818:<destination-pubkey>:hot-ice-creams", "<relay-url>" ],
-       [ "e", "<version-against-which-the-modification-was-made>", "<relay-url>' ],
-       [ "p", "<destination-pubkey>" ],
-       [ "e", "<version-to-be-merged>", "<relay-url>", "source" ]
-   ]
+  "content": "I added information about how to make hot ice-creams",
+  "kind": 818,
+  "tags": [
+    [ "a", "30818:<destination-pubkey>:hot-ice-creams", "<relay-url>" ],
+    [ "e", "<version-against-which-the-modification-was-made>", "<relay-url>' ],
+    [ "p", "<destination-pubkey>" ],
+    [ "e", "<version-to-be-merged>", "<relay-url>", "source" ]
+  ]
 }
 ```