[Neo Core Add] add char support

[Jim8y]

Description

We allows user to use char type in contract, however, user can not use char as the parameter, thus having this pr.

Fixes #

Type of change

• Optimization (the change is only an optimization)
• Style (the change is only a code style for better maintenance or standard purpose)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Test Configuration:

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

[Jim8y]

@cschuchardt88 according to the test, existing code alrady work, do i still need to update?

[cschuchardt88]

@cschuchardt88 according to the test, existing code alrady work, do i still need to update?

Doing it as (ushort)(object) is checked vs overflowing

[Jim8y]

(ushort)(object)

I dont understand, how could char to ushort be overflow?

[cschuchardt88]

(ushort)(object)

I dont understand, how could char to ushort be overflow?

UTF-32 can be 21-bits long for a single character. For an example emoji character.

[Jim8y]

@cschuchardt88

[shargon]

(ushort)(object)

I dont understand, how could char to ushort be overflow?

UTF-32 can be 21-bits long for a single character. For an example emoji character.

Could you add a UT for this case?

[Jim8y]

(ushort)(object)

I dont understand, how could char to ushort be overflow?

UTF-32 can be 21-bits long for a single character. For an example emoji character.

Could you add a UT for this case?

There is no such character that can be assigned to char making char longer than 2 bytes.

[cschuchardt88]

(ushort)(object)

I dont understand, how could char to ushort be overflow?

UTF-32 can be 21-bits long for a single character. For an example emoji character.

Could you add a UT for this case?

char only supports UTF-16 in dotnet, ushort is ok