[DOC] openerp: add missing parameter for search method

The `search` method of models has an additional keyword parameter, `count`.

It not being specified in the docs could lead people to inherit `search`
without defining it, which would result in a `TypeError` when called with
`count=`.

Closes #7451

openerp/models.py

@@ -1625,7 +1625,7 @@ class BaseModel(object):
 
     @api.returns('self')
     def search(self, cr, user, args, offset=0, limit=None, order=None, context=None, count=False):
-        """ search(args[, offset=0][, limit=None][, order=None])
+        """ search(args[, offset=0][, limit=None][, order=None][, count=False])
 
         Searches for records based on the ``args``
         :ref:`search domain <reference/orm/domains>`.
@@ -1635,6 +1635,7 @@ class BaseModel(object):
         :param int offset: number of results to ignore (default: none)
         :param int limit: maximum number of records to return (default: all)
         :param str order: sort string
+        :param bool count: if True, only counts and returns the number of matching records (default: False)
         :returns: at most ``limit`` records matching the search criteria
 
         :raise AccessError: * if user tries to bypass access rules for read on the requested object.