Document acronym (ETF)

[ysmartin]

ETF

Suggestion: AETF

Rationale: I understand WAET was changed because its pronounciation was confusing (was it?). But why removing the 'A' for accessibility? It appears in the acronyms of almost all other WAI works. Pronunciation is not a reason either, as both (ETF or AETF) would need to be spelled out.
Plus, ETF is an already popular acronym, as soon as I read it, Exchange Traded Funds came to my mind.

Note: if accepted, replace elsewhere as well.