[Accessibility] Add option to reduce precision when printing tensors to screen

[a-alhusaini]

It would make Nx a lot more accessible for screen readers if I could limit the precision of the output when printing tensors to screen.

I didn't know that the numbers Nx was printing to the screen were in scientific notation because I was skipping some of the digits with my screen reader (there is just too many of them)

This happenned here: elixir-nx/axon#526

I propose we add a config option that limits precision when tensors are printed ot the screen. Instead of a tensor that looks like this:

#Nx.Tensor<
  f32[1][10]
  EXLA.Backend<host:0, 0.3007448411.1655570452.243887>
  [
    [2.3431260944184697e-23, 4.296128036651581e-11, 1.0659236316176752e-17, 0.9999992847442627, 6.712944780263512e-22, 1.0, 2.8145804840526482e-22, 2.4531429665408666e-10, 9.463095196338145e-9, 2.6594868813845096e-6]
  ]
>

We would have

#Nx.Tensor<
  f32[1][10]
  EXLA.Backend<host:0, 0.3007448411.1655570452.243887>
  [
    [2.97e-23, 4.81e-11, 1.52e-17, 0.9927, 6.12e-22, 1.0, 2.82e-22, 2.66e-10, 9.45e-9, 2.46e-6]
  ]
>

This shortened format would make Nx a lot easier to interact with for blind users (like me)

[josevalim]

Hi @a-alhusaini! We should definitely do something because the precision we print is also misleading, f32 doesn't have such a large precision, and maybe fixing that will already improve this issue considerably. See #448.

[a-alhusaini]

the precision we print is also misleading,

I'm surprised I only noticed this when you pointed it out. This leads me to conclude that most Nx users don't really care about the exact numbers being printed to the screen. Maybe truncating the printed output should be a default instead of a configuration option?

Just an idea I had. Not sure if it is good or not.

[josevalim]

The precision it prints has additional digits which we should discard. Maybe nobody cares about the additional digits but they may care about missing digits.

I don't know either, just adding more context. :)