ts: Display more errors, E shortcut for editmode, Fix changelog

src/api/ApiError.tsx

src/api/Backend.tsx

src/api/api_v1_types.d.ts

src/components/DefaultLayout.tsx

src/components/EditModeProvider.tsx

src/pages/dynamic_course_listing.tsx

src/pages/dynamic_embed.tsx

src/pages/dynamic_player.tsx

src/pages/internal/changelog.tsx

src/pages/internal/import.tsx