updated gem-packages-desktop.txt

setup/gem-packages-desktop.txt

@@ -10,12 +10,13 @@ jgrep
 lolcat
 rbenv
 
-# mdl needs ruby >= 2.4.0 whereas Mac has 2.3.0, so install manually via
+# mdl needs ruby >= 2.4.0 whereas older Macs may have 2.3.0 - if so install manually via:
 #
-# brew install ruby
+#       brew install ruby
 #
-# GEM=/usr/local/Cellar/ruby/*/bin/gem  ./ruby_gem_install.sh mdl
+#       GEM=/usr/local/Cellar/ruby/*/bin/gem  ./ruby_gem_install.sh mdl
 #
 # will be picked up by new shells via .bash.d/paths.sh automatically detecting and adding ~/.gem/ruby/*/bin
 #
-# mdl
+# on macOS Catalina I now have Ruby 2.6 so this can install normally
+mdl