Improve C4324 warning reference

[Rageking8]

• Add "Remarks" and "Example" headings
• Change "structname" in warning message to "type" as C4324 also applies to class and union
• Add some details about "class/struct/union" and alignas in the remarks
• Improve example:
  • Remove superfluous main function and add /c flag
  • Prefer standard alignas over __declspec(align)
  • Extend the example with an empty struct and okay case
• Update metadata