Fix: --help summary for subcommands shows parents summary

spec/formatter_spec.cr

@@ -15,7 +15,18 @@ private class GreetCommand < Cling::MainCommand
   end
 end
 
+class WelcomeCommand < Cling::Command
+  def setup : Nil
+    @name = "welcome"
+    @summary = @description = "sends a friendly welcome message"
+  end
+
+  def run(arguments : Cling::Arguments, options : Cling::Options) : Nil
+  end
+end
+
 command = GreetCommand.new
+command.add_command WelcomeCommand.new
 formatter = Cling::Formatter.new
 
 describe Cling::Formatter do
@@ -26,6 +37,9 @@ describe Cling::Formatter do
     Usage:
     \tgreet <arguments> [options]
 
+    Commands:
+    \twelcome    sends a friendly welcome message
+
     Arguments:
     \tname    the name of the person (required)
 
@@ -45,6 +59,9 @@ describe Cling::Formatter do
     Usage:
     \tgreet <arguments> [options]
 
+    Commands:
+    \twelcome    sends a friendly welcome message
+
     Arguments:
     \tname    the name of the person (required)
 

src/cling/formatter.cr

@@ -97,7 +97,7 @@ module Cling
       io << "Commands:"
       commands.each do |cmd|
         io << "\n\t"
-        if summary = command.summary
+        if summary = cmd.summary
           cmd.name.ljust(io, max_space, ' ')
           io << summary
         else