uninstall: improve pronoun for multiple version message

When exactly two versions of a package were installed, the uninstall
message should not read "Remove them all with...", since only one
version remains.

"Remove all versions with..." is flexible enough to avoid being
interpreted as grammatically incorrect, and it still accurately
describes the general behavior of `brew uninstall --force`.

Library/Homebrew/cmd/uninstall.rb

@@ -25,7 +25,7 @@ module Homebrew
             versions = rack.subdirs.map(&:basename)
             verb = versions.length == 1 ? "is" : "are"
             puts "#{keg.name} #{versions.join(", ")} #{verb} still installed."
-            puts "Remove them all with `brew uninstall --force #{keg.name}`."
+            puts "Remove all versions with `brew uninstall --force #{keg.name}`."
           end
         end
       end