TechDocs etc update to Backstage roadmap (#8944)

* TechDocs etc update to Backstage roadmap

* fixup

Signed-off-by: Fredrik Adelöw <freben@gmail.com>

* Minor changes to roadmap

* prettier fixup

Signed-off-by: Emma Indal <emma.indahl@gmail.com>

Co-authored-by: Fredrik Adelöw <freben@gmail.com>
Co-authored-by: Emma Indal <emma.indahl@gmail.com>

.github/styles/vocab.txt

@@ -1,5 +1,7 @@
 abc
 accessors
+addon
+addons
 Airbrake
 Anddddd
 Apdex

docs/overview/roadmap.md

@@ -64,7 +64,7 @@ cycle will vary based on maintainer schedules.
 ### Backstage 1.0 (and following versions)
 
 During the first quarter of 2022, we plan to finalize and release version 1.0 of
-the Backstage platform (defined by the Core,
+the Backstage platform (which includes Core,
 [Catalog](https://backstage.io/docs/features/software-catalog/software-catalog-overview),
 [Scaffolder](https://backstage.io/docs/features/software-templates/software-templates-index)
 and [TechDocs](https://backstage.io/docs/features/techdocs/techdocs-overview)).
@@ -104,7 +104,16 @@ the maintainers’ radar, with clear interest expressed by the community.
 - **Security Plan (and Strategy):** The purpose of the Security Strategy is to
   move another step along the path to maturing the platform, setting the
   expectations of any adopters from a security standpoint.
-- **Search GA:**.
+- **Search 1.0:** Fix the few remaining issues to get Backstage Search platform
+  up to 1.0 ([here](https://github.com/backstage/backstage/milestone/27) and
+  [here](https://github.com/backstage/backstage/milestone/28))
+- **TechDocs Addon framework and Addons:** Addons are TechDocs features that are
+  added on top of the base docs like code experience. An example would be a
+  feature that showed comments on the page. We plan to add an Addon framework
+  and open source a selection of the Addons that we use internally at Spotify.
+  Further Addons can then be added by the Community.
+- **Composable Homepage 1.0:** Driving this to 1.0 by adding some composable
+  components.
 - **[GraphQL](https://graphql.org/) support:** Introduce the ability to query
   Backstage backend services with a standard query language for APIs.
 - **Telemetry:** To efficiently generate logging and metrics in such a way that