Introduce OpenAPI specs (#4351)

* wip

* wip

* wip

* Update index.ts

* Update gen-openapi-spec.ts

* Update api.ja-JP.md

* Fix

* Improve doc

* Update gen-openapi-spec.ts

* Update redoc.html

* Improve doc

* Update gen-openapi-spec.ts

* Improve doc

* Update CHANGELOG.md

src/server/api/endpoints/drive/files/show.ts

@@ -14,6 +14,8 @@ export const meta = {
 		'en-US': 'Get specified file of drive.'
 	},
 
+	tags: ['drive'],
+
 	requireCredential: true,
 
 	kind: 'drive-read',
@@ -37,6 +39,10 @@ export const meta = {
 		}
 	},
 
+	res: {
+		type: 'DriveFile',
+	},
+
 	errors: {
 		noSuchFile: {
 			message: 'No such file.',