message: docs: Add comments referencing the Solid spec where relevant
  Also some minor changes to completely match the spec there.
diff: @@ -8,7 +8,6 @@ import type { Representation } from '../../../src/ldp/representation/Representat
  import type { ResourceIdentifier } from '../../../src/ldp/representation/ResourceIdentifier';
  import type { ResourceStore } from '../../../src/storage/ResourceStore';
  import { ForbiddenHttpError } from '../../../src/util/errors/ForbiddenHttpError';
  -import { InternalServerError } from '../../../src/util/errors/InternalServerError';
  import { NotFoundHttpError } from '../../../src/util/errors/NotFoundHttpError';
  import { UnauthorizedHttpError } from '../../../src/util/errors/UnauthorizedHttpError';
  import { SingleRootIdentifierStrategy } from '../../../src/util/identifiers/SingleRootIdentifierStrategy';
  @@ -153,7 +152,7 @@ describe('A WebAclAuthorizer', (): void => {
  };
  const promise = authorizer.handle({ identifier, permissions, credentials });
  await expect(promise).rejects.toThrow('No ACL document found for root container');
  - await expect(promise).rejects.toThrow(InternalServerError);
  + await expect(promise).rejects.toThrow(ForbiddenHttpError);
  });
  it('allows an agent to append if they have write access.', async(): Promise<void> => {
  