help.merge-tools: do not double document merge tools Merge tools were being double documented in help system output due to functions being defined under multiple names in the merge tools dictionary. Establish a new dictionary for just the tools to document and use it from the help system so we don't get double output. Double documentation likely plagues other auto-documented items as well. It might be a good idea to eventually compare function instances to filter out duplicate entries from dictionaries passed to ``makeitemsdoc``. However, without an easy way to break ties, this may result in some functions being advertised over their modern equivalents. This would be a noble patch series. But it isn't one this author is willing to tackle at this time.