doc: remove some completed TODO items

doc/TODO.txt

@@ -5,14 +5,6 @@ TODO: auto-timestamps
 - SaveXyz shouldn't set created_at in the do-update branch
 - GetXyzByID should include `ErrItemIsDeleted` if item is soft-deleted
 
-TODO: primary-key
-- SaveXyz shouldn't set primary key if it's rowid
-
-TODO: foreign-key
-- Generated types should match foreign keys to the type of the column they point to
-
 TODO: modified-timestamps
 - set updated_at and created_at in SaveXYZ
 - soft delete option
-
-TODO: the `db_meta` table doesn't pass sqlite_lint