[mkgmap-dev] Commit r4855: improve documentation, esp. about --mdr7-del (options2.patch by Mike Baggaley)

Version mkgmap-r4855 was committed by gerd on Mon, 10 Jan 2022 improve documentation, esp. about --mdr7-del (options2.patch by Mike Baggaley) http://www.mkgmap.org.uk/websvn/revision.php?repname=mkgmap&rev=4855