Use camelCase parameter names in projected struct constructors

[Sergio0694]

This PR updates the codegen for projected struct constructors to use camelCase parameter names instead of underscore-prefixed field names, producing a cleaner public API surface.

Motivation

The current codegen for projected structs generates constructor parameters by prepending an underscore to the field name (e.g. _Stage, _BytesSent). This is not idiomatic C# — the standard convention for parameter names is camelCase.

Changes

helpers.h

Added a to_camel_case() utility function that:

• Lowercases the first character using invariant ASCII arithmetic (no locale dependency)
• Falls back to prepending an underscore if the first character is not an uppercase ASCII letter (e.g. a field named _Foo becomes __Foo), to avoid collisions with the original field name

code_writers.h

Updated the struct constructor codegen to use to_camel_case(field.name) for parameter names and assignments.

Example

// Before
public HttpProgress(HttpProgressStage _Stage, ulong _BytesSent, ulong? _TotalBytesToSend, ...)
{
    Stage = _Stage;
    BytesSent = _BytesSent;
    ...
}

// After
public HttpProgress(HttpProgressStage stage, ulong bytesSent, ulong? totalBytesToSend, ...)
{
    Stage = stage;
    BytesSent = bytesSent;
    ...
}

[Copilot]

Pull request overview

Updates the cswinrt projection generator so projected struct constructors use camelCase parameter names (instead of underscore-prefixed names), improving the public C# API surface.

Changes:

• Added to_camel_case() helper to convert PascalCase to camelCase for generated parameter names.
• Updated projected struct constructor generation to use camelCase parameter names and corresponding assignments.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
src/cswinrt/helpers.h	Adds to_camel_case() utility used by codegen to derive constructor parameter names.
src/cswinrt/code_writers.h	Switches projected struct constructor parameter naming and assignments to use to_camel_case(field.name).

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[manodasanW]

is this needed, can't we just use this.?