PSP22: Update selectors and add the Result in the signature of methods

[xgreenx]

Update selectors according to PSP22 naming of the interface(previous selectors were generated for PSP20).
Added the Result in the signature of the methods, because based on a conversation in the issue we finalized, how revert will work and how we can return the data during the revert to the caller(and finalized how it can be implemented during cross contract calls).

[0xMarkian]

Hey @cmichi @Noc2 @athei!
I see that you approved changes on this PR. Let's have it merged if you are okay.
We would love to move the process forward :)

[xlc]

This format is really hard to read due to the ABI defs. It will be better if there is a at glance view of everything. Simply moving ABI to bottom of the file is also helpful.

[xgreenx]

This format is really hard to read due to the ABI defs. It will be better if there is a at glance view of everything. Simply moving ABI to bottom of the file is also helpful.

I agree with you, that it is hard to read. Do you have ideas of how to make it more readable?
As a solution, we can add an example of how types described in the defs section can be represented(implemented) in Rust.

[Noc2]

Sounds good, I will merge the updates, but feel free to continue to improve readability.