More annotation types

[ghassanpl]

This is a general issue that describes ideas for new annotation types

• RConstructor() ?
• RAlias()/RUsing(); - for commenting using X = ...; declarations, so that generated documentation is better (probably other things too)
  • could be also very good for reflecting per-class typedefs
• RConstant(); - for constexprs
• ROperator();
• RNamespace() ?
• RTest() ? - for marking static methods as tests
• RVersion() ? - or should we get that information from, in order: git tags, git commit, datetime
• RContext() ?
• RDoc();
• RCategory(Name, ...attributes); - for grouping together class members; attributes like Order = Declaration/Alphabetic or Order = {Documentation = Alphabetic, Editor = Declaration }, Collapsed = true; stuff like Document applies to all members, etc.

[ghassanpl]

Also a nice idea:

RAdditional something like that that would allow for something like RAdditional(AddFlags = {InField = Flags, FlagType = AdditionalFlags, StartingAtBit = 16})