update docs to remove /alpha

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>

docs/integrations/bitbucketServer/discovery.md

@@ -29,10 +29,10 @@ yarn --cwd packages/backend add @backstage/plugin-catalog-backend-module-bitbuck
 And update your backend by adding the following line:
 
 ```ts title="packages/backend/src/index.ts"
-backend.add(import('@backstage/plugin-catalog-backend/alpha'));
+backend.add(import('@backstage/plugin-catalog-backend'));
 /* highlight-add-start */
 backend.add(
-  import('@backstage/plugin-catalog-backend-module-bitbucket-server/alpha'),
+  import('@backstage/plugin-catalog-backend-module-bitbucket-server'),
 );
 /* highlight-add-end */
 ```