Fix grammer in changeset and export default registry also

Signed-off-by: sblausten <sam@roadie.io>

.changeset/eighty-windows-brush.md

@@ -2,4 +2,4 @@
 '@backstage/plugin-tech-insights-backend': minor
 ---
 
-Make FactRetrieverRegistry injectable to overrider default implementation
+Make FactRetrieverRegistry injectable to override default implementation

plugins/tech-insights-backend/src/index.ts

@@ -26,5 +26,6 @@ export type {
 export type { PersistenceContext } from './service/persistence/persistenceContext';
 export { createFactRetrieverRegistration } from './service/fact/createFactRetriever';
 export type { FactRetrieverRegistry } from './service/fact/FactRetrieverRegistry';
+export { DefaultFactRetrieverRegistry } from './service/fact/FactRetrieverRegistry';
 export type { FactRetrieverRegistrationOptions } from './service/fact/createFactRetriever';
 export * from './service/fact/factRetrievers';