This update (Dec 22, 2017) of the search tool adds support for searching VBA macros in Excel, Word and Powerpoint files.
The whole point of this update is to increase the objects in the searched file where words can be searched for a match. VBA macros being made of text were certainly a good candidate for this update.
It's worth noting that whenever a match is found in VBA macros, double-clicking on it will actually open the corresponding application (Excel, Word or Powerpoint), open the file, open the VBA macro editor, open the VBA macro module, scroll to the corresponding row and then select it.
Whenever a search result finds a match in a VBA macro, the Macros field is tagged to the object column in the search result list, so there is no ambiguity where this match is located.
Searching VBA macros does not work currently if the VBA macros are password protected (whether or not the file itself is password protected).