ConstShared so an item reads the same wherever it is listed: the formula autocomplete
(NamedItemsPanel) and the Insert Function dialog. Presentational only — the host owns the
row element, its selection styling and its events. The name carries the class named-item-name,
for a host that styles it (the dialog sets it in the monospace font).
The content of one row in a list of functions, names and tables — the kind glyph, the name, an optional trailing category and an optional summary under it.