uninstall: notify on multiple versions removed.

Closes Homebrew/homebrew#34398.

Closes Homebrew/homebrew#34445.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>

Library/Homebrew/cmd/uninstall.rb

@@ -12,6 +12,13 @@ module Homebrew
           keg.unlink
           keg.uninstall
           rm_pin keg.name
+
+          rack = keg/".."
+          if rack.directory?
+            versions = rack.subdirs.map(&:basename).join(", ")
+            puts "#{keg.name} #{versions} are still installed."
+            puts "Remove them all with `brew uninstall --force #{keg.name}`."
+          end
         end
       end
     else