Kill number prefixes for good

specification/targets.yaml

@@ -1,17 +1,17 @@
 targets:
   main:  # arbitrary name to identify this build target
     files:  # the sort order of files to cat
-      - 0-intro.rst
-      - 1-client_server_api.rst
-      - { 1: 0-events.rst }
-      - { 1: 0-event_signing.rst }
-      - 2-modules.rst
-      - { 1: 0-feature_profiles.rst }
+      - intro.rst
+      - client_server_api.rst
+      - { 1: events.rst }
+      - { 1: event_signing.rst }
+      - modules.rst
+      - { 1: feature_profiles.rst }
       - { 1: "group:modules" }  # reference a group of files
-      - 3-application_service_api.rst
-      - 4-server_server_api.rst
-      - 5-identity_servers.rst
-      - 6-appendices.rst
+      - application_service_api.rst
+      - server_server_api.rst
+      - identity_servers.rst
+      - appendices.rst
 groups:  # reusable blobs of files when prefixed with 'group:'
   modules:
     - modules/instant_messaging.rst