Fix inspect for non-decimal negative integers

[fhunleth]

Before:

iex> inspect(-1, base: :hex)
"0x-1"

After:

iex> inspect(-1, base: :hex)
"-0x1"

This change also applies to the octal and binary base options.

[NobbZ]

Negative non-decimals with an unary minus to display signedness feels odd in general.

If bitwidth is known use 2-complement or if not either use decimal output or fail.

This is just an opinion though...

[wojtekmach]

Negative non-decimals with an unary minus to display signedness feels odd in general.

one way to look at it is that -0x1 is valid Elixir syntax and 0x-1 is not.

[josevalim]

❤️ 💚 💙 💛 💜

[fhunleth]

All of you are quick with reviews! Thanks!