document changes in standards for command-line arguments

scripts that use unnamed arguments to build page titles
(often through lists named titleParts or pageTitle)
are going to change:
http://lists.wikimedia.org/pipermail/pywikipedia-l/2014-June/008905.html

also fixed a typo

Change-Id: I3d0c64bd0f4aac2a2c3cf375d84e77cb364868ad
Merge "document changes in standards for command-line arguments"