Added information about the properties of the results of API calls
to action=paraminfo, including information about "property groups":
what should the prop parameter be set to to get that property.
Uses the same format for types as parameters already do.
The output format of some modules doesn't fit this, so the result
properties for them weren't added, or only partially.
Partially implemented modules:
* expandtemplates:
parsetree is in its own tag
* protect, allusers, backlinks, deletedrevs, info, imageinfo,
logevents, querypage, recentchanges, revisions, searchinfo,
usercontribs, userinfo, users, watchlist, upload:
response with partially complex structure
Not implemented modules:
* feedcontributions, feedwatchlist, opensearch, rds:
non-standard reponse
* help:
error is normal response; not very useful for automated tools anyway
* paraminfo, parse, pageprops, siteinfo, userrights:
response with complex structure
Change-Id: Iff2a9bef79f994e73eef3062b4dd5461bff968ab
Follow up to I0d6c654a7354ba77e65e338423952a6a78c1150f.
I have also added a URL to a help page on mw.org.
Change-Id: Ie223930cfc313aff150e2dcfd70b74bf4360a8a8
