Usage: pub global activate <package> [version-constraint] (#2051)

diff --git a/lib/src/command/global_activate.dart b/lib/src/command/global_activate.dart
index 4aca1b0..be966ae 100644
--- a/lib/src/command/global_activate.dart
+++ b/lib/src/command/global_activate.dart
@@ -14,7 +14,7 @@
 class GlobalActivateCommand extends PubCommand {
   String get name => "activate";
   String get description => "Make a package's executables globally available.";
-  String get invocation => "pub global activate <package...>";
+  String get invocation => "pub global activate <package> [version-constraint]";
 
   GlobalActivateCommand() {
     argParser.addOption("source",