Mention the existence of the .tupleof property

[MrcSnm]

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[ntrel]

This seems to repeat the information here.

There are actually many properties not documented on the properties page, as they are instead linked to under 'see also' (just before the .init Property section). This includes links to class properties and struct properties. (Arguably the page could make this clearer).

[ntrel]

(Arguably the page could make this clearer).

#4173 adds headings for derived and user-defined type properties, keeping the existing links. These will then appear in the table of contents for the page, making them more accessible.