proper support for int16 format.

[andrueastman]

Is your feature request related to a problem? Please describe the problem.

Follow up to #5611

Adding proper support for int16 would mean adding a new method to the parse node and serialization writer interfaces, which means a breaking change.

After changes in #5614, the int16 format is mapped to the integer type. However, languages

• C# could use the short type
• Golang could use int16 type
• Java could use the short type.

At the next breaking change we should take advantage of the opportunity to add support for the format for more precision.

Client library/SDK language

None

Describe the solution you'd like

Support the int16 format for languages that provide types with the level of precision.

Additional context

No response