Fix lint errors (except @typescript-eslint/prefer-nullish-coalescing) (#9311)

* `yarn workspace client run lint --fix`

* `eslint-disable-next-line no-var` for service worker self

* A few more manual sw fixes

* word change

packages/sw/src/scripts/operations.ts

@@ -2,6 +2,9 @@
  * Operations
  * 各種操作
  */
+
+// TODO: remove this declaration when https://github.com/microsoft/TypeScript/issues/11781 closes
+// eslint-disable-next-line no-var
 declare var self: ServiceWorkerGlobalScope;
 
 import * as Misskey from 'misskey-js';