add some sort of spec for lablled tags

spec.md

@@ -23,6 +23,7 @@
   - [Delimited Email addresses: `<[email protected]>`](#delimited-email-addresses)
   - [Delimited Links: `<http://example.org>`](#delimited-links)
   - [Labeled Links: `[Name](url)`](#labled-links)
+  - [Labeled hashtags: `[Tag][#tag]`](#labeled-tags)
 
 ## Text Enhancements
 
@@ -182,6 +183,13 @@ Optionally, a client can implement a system to trust a domain (a "don't ask agai
 
 URL parsing allows all valid URLs, no restrictions on schemes, no whitelist is needed, because the format already specifies that it is a link.
 
+
+<a name="labeled-tags" />
+
+### Labelled hashtags
+
+The idea is to have hashtags but labelled with an alternative text. This feature is very unique and less seen in other IMs.
+
 ## Ideas For The Future:
 
 ### `:emoji:`