Allow defining nested structure in wrap type

[joente]

Description

This pull request allows defining nested structure in wrap type.

Consider the following structure:

set_type('M1', {
  id: '#',
  num: 'int',
}, true);

set_type('T1', {
  metrics: '&{M1}',
}, true, true);

set_type('C1', {
  x: '#',
  name: 'str',
  type: '&T1',
}, true);

In this scenario, we actually need "C1" to wrap an object and the types "T1" and "M1" are just defined because of the nested structure.

With this pull request implemented, we can write the above as the following:

set_type('C2', {
  x: '#',
  name: 'str',
  type: {
    metrics: [{
      id: '#',
      num: 'int',
    }],
  },
}, true);

Note that for each nested structure, in this case type and metrics, the & flag is implied. For the "id" to be returned, the # property must be explicitly defined, otherwise the type will be created with the "hide id" flag and it will not appear in the result.

Type of change

• New feature (non-breaking change which adds functionality)

How Has This Been Tested?

• New test wrap nested

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• New and existing unit tests pass locally with my changes