(bug 31883) Limit of some params is not documented in API autodoc

(bug 31883) Limit of some params is not documented in API autodoc

Original bug description: Limit of bkusers of list=blocks and titles of
action=query is not documented in API help

For that params no PARAM_TYPE was set, determine the type with the same
code as in r85758 (action=paraminfo) and its modification in r86917

Move the adding of that text out of the else, than the doc is also
added to params with more than 50 default values
(which looks to be intend of that piece of code).

Change-Id: I3fa59d2a7ae688da79dab57dc0576a69f786cca5