update show-topic help

src/Steeltoe.Cli/ShowTopicCommand.cs

@@ -21,10 +21,10 @@ namespace Steeltoe.Cli
     [Command(Description = "Displays documentation on a topic",
         ExtendedHelpText = @"
 Overview:
-  *** under construction ***
+  Displays documentation for various topics.  Run with no arguments for a list of available topics.
 
 Examples:
-  Display documentation on autodetection:
+  Display documentation for autodetection:
   $ st show-topic autodetection"
     )]
     public class ShowTopicCommand : Command

test/Steeltoe.Cli.Test/ShowTopicFeature.cs

@@ -35,9 +35,9 @@ namespace Steeltoe.Cli.Test
                     "Options:",
                     "-?|-h|--help Show help information",
                     "Overview:",
-                    "*** under construction ***",
+                    "Displays documentation for various topics. Run with no arguments for a list of available topics.",
                     "Examples:",
-                    "Display documentation on autodetection:",
+                    "Display documentation for autodetection:",
                     "$ st show-topic autodetection",
                 })
             );