[Search] add how to guide for indexing TechDocs documents (#7625)

* add how to guide for indexing techdocs documents

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

* add step of how to add techdocs to search type filter

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

docs/features/search/README.md

@@ -113,10 +113,10 @@ search engines.
 
 ## Plugins Integrated with Search
 
-| Plugin   | Support Status |
-| -------- | -------------- |
-| Catalog  | ✅             |
-| TechDocs | ✅             |
+| Plugin                                                         | Support Status |
+| -------------------------------------------------------------- | -------------- |
+| Catalog                                                        | ✅             |
+| [TechDocs](./how-to-guides.md#how-to-index-techdocs-documents) | ✅             |
 
 [Reach out to us](#get-involved) if you want to chat about support for more
 plugins integrated to search.

docs/features/search/how-to-guides.md

@@ -44,3 +44,55 @@ const app = createApp({
   ],
 });
 ```
+
+## How to index TechDocs documents
+
+The techdocs-plugin has supported integrations to Search, meaning that it
+provides a default collator ready to be used.
+
+The purpose of this how-to guide is to walk you through how to register the
+[DefaultTechDocsCollator](https://github.com/backstage/backstage/blob/master/plugins/techdocs-backend/src/search/DefaultTechDocsCollator.ts)
+in your App in two steps, so that you can get TechDocs documents indexed.
+
+If you have been through the
+[getting started guide](https://backstage.io/docs/features/search/getting-started)
+already, you should have the `packages/backend/src/plugins/search.ts` file
+available. If you have that, you can jump to the first step of this guide, if
+not - start by go through the getting started guide.
+
+1. Import the DefaultTechDocsCollator from `@backstage/plugin-techdocs-backend`.
+
+```typescript
+import { DefaultTechDocsCollator } from '@backstage/plugin-techdocs-backend';
+```
+
+2. Register the DefaultTechDocsCollator with the IndexBuilder.
+
+```typescript
+indexBuilder.addCollator({
+  defaultRefreshIntervalSeconds: 600,
+  collator: DefaultTechDocsCollator.fromConfig(config, {
+    discovery,
+    logger,
+  }),
+});
+```
+
+You should now have your TechDocs documents indexed to your search engine of
+choice!
+
+If you want your users to be able to filter down to the techdocs type when
+searching. You can update your `SearchPage.tsx` file in
+`packages/app/src/components/search` by adding `techdocs` to the list of values
+of the `SearchType` component.
+
+```tsx
+<Paper className={classes.filters}>
+  <SearchType
+    values={['techdocs', 'software-catalog']}
+    name="type"
+    defaultValue="software-catalog"
+  />
+  ...
+</Paper>
+```