Add feature to convert from top-level-statements to Program.Main form

[CyrusNajmabadi]

Comes with style option: csharp_style_prefer_top_level_statements

Looks like:

Todo:

• Provide way to go from Program.Main to top-level-statements
• Provide refactoring on top of fixer to go the other direction if the style is there, but set to hidden
• Have the new-file generation code respect this option if present.

[Youssef1313]

That should be in Analyzers layer.

[CyrusNajmabadi]

this matches the ConvertNamespace fixer work. we can move both over at the same time if appropriate.

[Youssef1313]

@CyrusNajmabadi This causes bugs like #45569

There are many codefixes that are misplaced in Features. I think it's better if future codefixes are placed properly making the future work to move everything to Analyzers more manageable.

[CyrusNajmabadi]

so, i'm amenable to that, but i think ti should be done as a general work item that also ensures that the analyzer/fixer layer has all the appropraite other extensions/modules needed to make that work.

[CyrusNajmabadi]

Perhaps a test or two with a file that has a file header, just to make sure that is maintained?

Will do!