Alias categories

Issue provider aliases should use the CakeAliasConstants.MainCakeAliasCategory and CakeAliasConstants.CodeAnalysisProviderCakeAliasCategory constants for defining their category:

[CakeAliasCategory(CakeAliasConstants.MainCakeAliasCategory)]
public static class MyIssueProviderAliases
{
    [CakeMethodAlias]
    [CakeAliasCategory(CakeAliasConstants.CodeAnalysisProviderCakeAliasCategory)]
    public static ICodeAnalysisProvider MyIssueProvider(
        this ICakeContext context)
    {
    }
}