NIP-23, NIP-99: remove NIP-12 mention

Author: AsaiToshiya

23.md

@@ -20,7 +20,7 @@ The `.content` of these events should be a string text in Markdown syntax. To ma
 
 ### Metadata
 
-For the date of the last update the `.created_at` field should be used, for "tags"/"hashtags" (i.e. topics about which the event might be of relevance) the `t` tag should be used, as per NIP-12.
+For the date of the last update the `.created_at` field should be used, for "tags"/"hashtags" (i.e. topics about which the event might be of relevance) the `t` tag should be used.
 
 Other metadata fields can be added as tags to the event as necessary. Here we standardize 4 that may be useful, although they remain strictly optional:
 

99.md

@@ -26,7 +26,7 @@ The `.pubkey` field of these events are treated as the party creating the listin
 
 ### Metadata
 
-- For "tags"/"hashtags" (i.e. categories or keywords of relevance for the listing) the `"t"` event tag should be used, as per [NIP-12](12.md).
+- For "tags"/"hashtags" (i.e. categories or keywords of relevance for the listing) the `"t"` event tag should be used.
 - For images, whether included in the markdown content or not, clients SHOULD use `image` tags as described in [NIP-58](58.md). This allows clients to display images in carousel format more easily.
 
 The following tags, used for structured metadata, are standardized and SHOULD be included. Other tags may be added as necessary.