Support dynamic imports in addRelativeDeclarationExtensions

[cjpearson]

Describe the feature

When generating declarations, some types are automatically inlined. For example, my declaration file looks something like this:

export declare const helloWorld: (foo: import("../../types/foo").Foo) => Promise<string>;

It would be helpful for addRelativeDeclarationExtensions to also handle these imports so the declarations are compatible with node16 resolution.

export declare const helloWorld: (foo: import("../../types/foo.js").Foo) => Promise<string>;

Additional information

• Would you be willing to help implement this feature?