documentation

Pull request #1355: feature/ZBXNEXT-6554-6.0-D: Return value limit raised to 16MB.

Merge in WEB/documentation from feature/ZBXNEXT-6554-6.0-D to release/6.0

* commit '3041db33367e19002e50665adad8ada2278c5995':
  [ZBXNEXT-6554] Removed redundant info on output limit for system.sw.packages
  [ZBXNEXT-6554] Fixed links
  [ZBXNEXT-6554] Restored note on user parameters limit; refined wording
  [ZBXNEXT-6654] Removed unnecessary sentence (was added when resolving merge conflict)
  [ZBXNEXT-6554] Return value limit raised to 16MB