category doc capitalization

see #558

Some stats

Count by category
{ Internal: 10,
  Type: 3,
  List: 75,
  Function: 37,
  Object: 37,
  Logic: 8,
  Relation: 14,
  Math: 18,
  String: 13 }

Count by number of categories
{ '1': 209, '2': 3 }

It looks to me like every external function has a category. Some internal ones still do not.

Question: can we remove the TODOs or move them to the jsdocs? Some of them cause problems with the `dox` parser