Bump typescript and remove override

[rotu]

Previously, npm install would fail with an issue like below, due to us using a version of typescript which the dependency typedoc did not accept as a valid peer dependency. Now we bump to a more recent version of typescript.

npm error code ERESOLVE
npm error ERESOLVE could not resolve
npm error
npm error While resolving: [email protected]
npm error Found: [email protected]
npm error node_modules/typescript
npm error   dev typescript@"~4.9.0" from the root project
npm error   typescript@"next" from [email protected]
npm error   node_modules/downlevel-dts
npm error     dev downlevel-dts@"^0.11.0" from the root project
npm error   6 more (eslint-plugin-solid, ...)
npm error
npm error Could not resolve dependency:
npm error peer typescript@"5.0.x || 5.1.x || 5.2.x || 5.3.x || 5.4.x || 5.5.x || 5.6.x || 5.7.x" from [email protected]
npm error node_modules/typedoc
npm error   dev typedoc@"^0.27.6" from the root project
npm error
npm error Conflicting peer dependency: [email protected]
npm error node_modules/typescript
npm error   peer typescript@"5.0.x || 5.1.x || 5.2.x || 5.3.x || 5.4.x || 5.5.x || 5.6.x || 5.7.x" from [email protected]
npm error   node_modules/typedoc
npm error     dev typedoc@"^0.27.6" from the root project
npm error
npm error Fix the upstream dependency conflict, or retry
npm error this command with --force or --legacy-peer-deps
npm error to accept an incorrect (and potentially broken) dependency resolution.
npm error
npm error

[aminya]

This might affect the type compatibility for older TypeScript versions. We have to be careful.

[rotu]

This might affect the type compatibility for older TypeScript versions. We have to be careful.

is that what downlevel-dts and test/typings-compatibility are supposed to ensure?