bip387: Update to Specification type

README.mediawiki

@@ -1392,7 +1392,7 @@ users (see also: [https://en.bitcoin.it/wiki/Economic_majority economic majority
 | Applications
 | Tapscript Multisig Output Script Descriptors
 | Pieter Wuille, Ava Chow
-| Informational
+| Specification
 | Deployed
 |- style="background-color: #ffffcf"
 | [[bip-0388.mediawiki|388]]

bip-0387.mediawiki

@@ -5,7 +5,7 @@
   Authors: Pieter Wuille <pieter@wuille.net>
            Ava Chow <me@achow101.com>
   Status: Deployed
-  Type: Informational
+  Type: Specification
   Assigned: 2024-04-17
   License: BSD-2-Clause
   Requires: 380