Update helptext to show Default Verb

Author: moh-hassan

src/CommandLine/Text/HelpText.cs

@@ -853,7 +853,7 @@ private IEnumerable<Specification> AdaptVerbsToSpecifications(IEnumerable<Type>
                                       string.Empty,
                                       verbTuple.Item1.Name,
                                       false,
-                                      verbTuple.Item1.HelpText,
+                                      verbTuple.Item1.IsDefault?  "(Default Verb) "+verbTuple.Item1.HelpText: verbTuple.Item1.HelpText,  //Default verb
                                       string.Empty,
                                       verbTuple.Item1.Hidden);
             if (autoHelp)

tests/CommandLine.Tests/Fakes/Verb_Fakes.cs

@@ -18,7 +18,20 @@ public class Add_Verb
         [Value(0)]
         public string FileName { get; set; }
     }
+    [Verb("add", isDefault:true,HelpText = "Add file contents to the index.")]
+    public class Add_Verb_As_Default
+    {
+        [Option('p', "patch", SetName = "mode-p",
+            HelpText = "Interactively choose hunks of patch between the index and the work tree and add them to the index.")]
+        public bool Patch { get; set; }
 
+        [Option('f', "force", SetName = "mode-f",
+            HelpText = "Allow adding otherwise ignored files.")]
+        public bool Force { get; set; }
+
+        [Value(0)]
+        public string FileName { get; set; }
+    }
     [Verb("commit", HelpText = "Record changes to the repository.")]
     public class Commit_Verb
     {

tests/CommandLine.Tests/Unit/ParserTests.cs

@@ -370,7 +370,30 @@ public void Implicit_help_screen_in_verb_scenario()
             lines[8].Should().BeEquivalentTo("version    Display version information.");
             // Teardown
         }
+       
+        [Fact]
+        public void Help_screen_in_default_verb_scenario()
+        {
+            // Fixture setup
+            var help = new StringWriter();
+            var sut = new Parser(config => config.HelpWriter = help);
 
+            // Exercise system
+            sut.ParseArguments<Add_Verb_As_Default, Commit_Verb, Clone_Verb>(new string[] {"--help" });
+            var result = help.ToString();
+         
+            // Verify outcome
+            result.Length.Should().BeGreaterThan(0);
+            var lines = result.ToNotEmptyLines().TrimStringArray();
+            lines[0].Should().Be(HeadingInfo.Default.ToString());
+            lines[1].Should().Be(CopyrightInfo.Default.ToString());
+            lines[2].Should().BeEquivalentTo("add        (Default Verb) Add file contents to the index.");
+            lines[3].Should().BeEquivalentTo("commit     Record changes to the repository.");
+            lines[4].Should().BeEquivalentTo("clone      Clone a repository into a new directory.");
+            lines[5].Should().BeEquivalentTo("help       Display more information on a specific command.");
+            lines[6].Should().BeEquivalentTo("version    Display version information.");
+            
+        }
         [Fact]
         public void Double_dash_help_dispalys_verbs_index_in_verbs_scenario()
         {