Load .wt.json snippets from parent directories

[carlos-zamora]

Summary of the Pull Request

Adds logic such that local snippets from .wt.json files are imported not only at the current directory, but also in the parent directories.

References and Relevant Issues

Spec: https://github.com/microsoft/terminal/blob/main/doc/specs/%231595%20-%20Suggestions%20UI/Snippets.md

Validation Steps Performed

D:\test\.wt.json: contains Hello --> hello (parent)
D:\test\inner_dir\.wt.json: contains Hello --> hello

• In D:\test\...
  • ✅ Hello command outputs hello (parent)
  • ✅ commands from inner_dir not shown
• In D:\test\inner_dir\...
  • ✅ Hello command outputs hello
  • ✅ commands from D:\test are shown

PR Checklist

Closes #17805

[lhecker]

Just nits.

[lhecker]

You can remove the string copy, but it looks ugly so maybe don't.

Suggested change

	directories.push_back(directory);
	const auto parentPath = directory.parent_path();
	auto parentPath = directory.parent_path();
	const auto done = directory == parentPath;
	directories.push_back(std::move(directory));
	if (done)
	{
	break;
	}
	directory = std::move(parentPath);