`winsound.SND_APPLICATION` is not documented

[aisk]

winsound.SND_APPLICATION exists for a very long time but it's not documented unlike other winsound.SND_* consts, so I think we should document it.

Linked PRs

• gh-131327: Document winsound.SND_APPLICATION #131328
• [3.12] gh-131327: Document winsound.SND_APPLICATION (GH-131328) #131329
• [3.13] gh-131327: Document winsound.SND_APPLICATION (GH-131328) #131330