Feature summary (what you would like to be able to do and where):
Add the possibility to change the sorting order, like in Special:Search on most wikis, in SearchPageGenerator, described on this page on Mediawiki.

Use case(s) (list the steps that you performed to discover that problem, and describe the actual underlying problem which you want to solve. Do not describe only a solution):
When using SearchPageGenerator to edit a few articles (like 5-10 %) from a large search (in my example about 200K results), restarting the bot means going through all the articles already checked, which increased the time to process every results and the number of requests to the API. Caching the results can also solve this issue, but it's not always possible/desirable.

Benefits (why should this be implemented?):

• it will increase the usefulness of pywikibot (not needed to use another implementation instead)
• it can reduce the number of requests to the API (i.e. more work done in the same time)
• it can reduce the complexity of some code trying to work around