[Checkins] [zopefoundation/Products.ZCatalog] 5e9e1b: improve interface docstrings

[Dieter Maurer]

  Branch: refs/heads/resultset_intersection#55
  Home:   https://github.com/zopefoundation/Products.ZCatalog
  Commit: 5e9e1b523b8e0c5bedc532b07d2257aff8db9af1
      https://github.com/zopefoundation/Products.ZCatalog/commit/5e9e1b523b8e0c5bedc532b07d2257aff8db9af1
  Author: dieter <dieter at handshake.de>
  Date:   2019-03-08 (Fri, 08 Mar 2019)

  Changed paths:
    M src/Products/PluginIndexes/interfaces.py

  Log Message:
  -----------
  improve interface docstrings