Allow adding options in menu and picker

[Philipp-M]

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This PR allows retaining the current selected option in either the menu or the picker, when calling score (as long, as it's still in there, after calling score). This is useful when extending the options later (via a new function add_options) in the picker or menu, which is the second addition in this PR.

This change is a requirement for #2507. In itself it doesn't change the current behavior of the editor. In #2507, this is needed, because multiple language-servers send their results async (e.g. completion, code-actions or symbol-picker)