merge HelpBuilderExtensions into HelpBuilder

src/System.CommandLine.ApiCompatibility.Tests/ApiCompatibilityApprovalTests.System_CommandLine_api_is_not_changed.approved.txt

@@ -187,8 +187,10 @@ System.CommandLine.Help
     public System.Int32 MaxWidth { get; }
     public System.Void CustomizeLayout(System.Func<HelpContext,System.Collections.Generic.IEnumerable<System.Action<HelpContext>>> getLayout)
     public System.Void CustomizeSymbol(System.CommandLine.Symbol symbol, System.Func<HelpContext,System.String> firstColumnText = null, System.Func<HelpContext,System.String> secondColumnText = null, System.Func<HelpContext,System.String> defaultValue = null)
+    public System.Void CustomizeSymbol(System.CommandLine.Symbol symbol, System.String firstColumnText = null, System.String secondColumnText = null, System.String defaultValue = null)
     public TwoColumnHelpRow GetTwoColumnRow(System.CommandLine.Symbol symbol, HelpContext context)
     public System.Void Write(HelpContext context)
+    public System.Void Write(System.CommandLine.Command command, System.IO.TextWriter writer)
     public System.Void WriteColumns(System.Collections.Generic.IReadOnlyList<TwoColumnHelpRow> items, HelpContext context)
    static class Default
     public static System.Action<HelpContext> AdditionalArgumentsSection()
@@ -203,9 +205,6 @@ System.CommandLine.Help
     public static System.Action<HelpContext> OptionsSection()
     public static System.Action<HelpContext> SubcommandsSection()
     public static System.Action<HelpContext> SynopsisSection()
-  public static class HelpBuilderExtensions
-    public static System.Void CustomizeSymbol(this HelpBuilder builder, System.CommandLine.Symbol symbol, System.String firstColumnText = null, System.String secondColumnText = null, System.String defaultValue = null)
-    public static System.Void Write(this HelpBuilder helpBuilder, System.CommandLine.Command command, System.IO.TextWriter writer)
   public class HelpContext
     .ctor(HelpBuilder helpBuilder, System.CommandLine.Command command, System.IO.TextWriter output, System.CommandLine.ParseResult parseResult = null)
     public System.CommandLine.Command Command { get; }

src/System.CommandLine/Argument{T}.cs

@@ -169,11 +169,15 @@ public void AcceptLegalFileNamesOnly()
         {
             if (default(T) is null && typeof(T) != typeof(string))
             {
-                if (typeof(T).IsArray)
+#if NET7_0_OR_GREATER
+                if (typeof(T).IsSZArray)
+#else
+                if (typeof(T).IsArray && typeof(T).GetArrayRank() == 1)
+#endif
                 {
                     return (T?)(object)Array.CreateInstance(typeof(T).GetElementType()!, 0);
                 }
-                else if (typeof(T).IsGenericType)
+                else if (typeof(T).IsConstructedGenericType)
                 {
                     var genericTypeDefinition = typeof(T).GetGenericTypeDefinition();
 

src/System.CommandLine/Help/HelpBuilderExtensions.cs

@@ -5,38 +5,30 @@
 
 namespace System.CommandLine.Help
 {
-    /// <summary>
-    /// Provides extension methods for the help builder.
-    /// </summary>
-    public static class HelpBuilderExtensions
+    public partial class HelpBuilder
     {
         /// <summary>
         /// Specifies custom help details for a specific symbol.
         /// </summary>
-        /// <param name="builder">The help builder to write with.</param>
         /// <param name="symbol">The symbol to customize the help details for.</param>
         /// <param name="firstColumnText">A delegate to display the first help column (typically name and usage information).</param>
         /// <param name="secondColumnText">A delegate to display second help column (typically the description).</param>
         /// <param name="defaultValue">The displayed default value for the symbol.</param>
-        public static void CustomizeSymbol(
-            this HelpBuilder builder,
+        public void CustomizeSymbol(
             Symbol symbol,
             string? firstColumnText = null,
             string? secondColumnText = null,
             string? defaultValue = null)
         {
-            builder.CustomizeSymbol(symbol, _ => firstColumnText, _ => secondColumnText, _ => defaultValue);
+            CustomizeSymbol(symbol, _ => firstColumnText, _ => secondColumnText, _ => defaultValue);
         }
 
         /// <summary>
         /// Writes help output for the specified command.
         /// </summary>
-        public static void Write(
-            this HelpBuilder helpBuilder,
-            Command command,
-            TextWriter writer)
+        public void Write(Command command, TextWriter writer)
         {
-            helpBuilder.Write(new HelpContext(helpBuilder, command, writer));
+            Write(new HelpContext(this, command, writer));
         }
     }
 }