Add a content API method which lists mods that loaded or edited an asset.

/// <summary>Get a list of mods which loaded or edited the current version of a given asset.</summary>
/// <param name="assetName">The asset name to check.</param>
public IEnumerable<IModInfo> GetModsWhichInterceptedAsset(string assetName);

Future SMAPI updates might add an equivalent feature, but I don't have any plans to implement this ticket specifically. I'll close this ticket since GitHub issues aren't really the place to track long-term suggestions/ideas.