Resolve fixme-s and todo-s

[szepeviktor]

Problem

Issues are stored in the code, not here on GitHub.

Solution

Work more! 🙃

Additional context

git grep --extended-regexp --ignore-case '\b(TODO|FIXME)\b'

compat/src-deprecated/functions.php: * @todo This function needs to be fixed because we are no longer storing
src/Abstracts/MergeTag.php:     //      @todo throws warning - cannot bind instance to static closure
src/Admin/PostType.php:         // @todo #h1kf7 `enabled` key is overwritten below.
src/Admin/PostType.php:      * @todo
src/Admin/Wizard.php:        * @todo
src/Store/Recipient.php: * @todo Refactor the class so it uses Storage trait.
src/Utils/EDDUpdater.php:               /* Translators: @todo */