Adding __repr__ for unions

[Intuity]

Adds __repr__ and __str__ to union to print out all members, also adjusts the formatting of structs to make it easier to follow:

Instruction: 0x12345678 (union):
 |- raw     -> Unsigned Scalar[32]: 0x12345678 (32 bits)
 |- add     -> Add: 0x12345678
                |- [ 1: 0] op    = 0x0
                |- [ 6: 2] tgt   = 0x1E
                |- [11: 7] src_a = 0xC
                |- [16:12] src_b = 0x5
 |- add_imm -> Add: 0x12345678
                |- [ 1: 0] op    = 0x0
                |- [ 6: 2] tgt   = 0x1E
                |- [11: 7] src_a = 0xC
                |- [16:12] src_b = 0x5

[Copilot]

Pull Request Overview

This PR adds string representation methods (__repr__ and __str__) to union types and improves the formatting of struct string representations. The changes enhance debugging and display capabilities by providing hierarchical, tree-like output that shows all union members and their values.

• Adds __str__ and __repr__ methods to union types to display all member fields with proper indentation
• Updates struct formatting to use tree-like symbols and proper zero-padding for hex values
• Enhances scalar type string representation with more descriptive naming and formatting

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
packtype/types/union.py	Implements __str__ and __repr__ methods for union display with tree formatting
packtype/types/scalar.py	Updates scalar string representation with descriptive naming and hex formatting
packtype/types/assembly.py	Improves struct formatting with tree symbols and proper hex padding
tests/pysyntax/test_union.py	Adds test coverage for union string representation
tests/pysyntax/test_struct.py	Adds test coverage for updated struct string representation

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}

[OisinRobinson]

With offline discussion about how the print looks these changes look good to me- Approved.