Docs: type 'unknown' missing from 'Everydad Types'

[rajinder-yadav]

Can someone please add the definition of the 'unknown' type and clearly describe the purpose of it, and how is differs from the type 'any'.

Sample coding show proper use of 'unknown' as well as the context to use it over 'any' would also be benificial.

[natepmay]

This explanation/distinction is given in the "More on Functions" chapter of the handbook: https://www.typescriptlang.org/docs/handbook/2/functions.html#unknown