Option.AcceptLegalFilePathsOnly should return void

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

@@ -199,7 +199,7 @@ System.CommandLine
     .ctor(System.String name, Func<T> defaultValueFactory, System.String description = null)
     .ctor(System.String[] aliases, Func<T> defaultValueFactory, System.String description = null)
     public Option<T> AcceptLegalFileNamesOnly()
-    public Option<T> AcceptLegalFilePathsOnly()
+    public System.Void AcceptLegalFilePathsOnly()
     public System.Void AcceptOnlyFromAmong(System.String[] values)
     public System.Void SetDefaultValue(T value)
     public System.Void SetDefaultValueFactory(Func<T> defaultValueFactory)

src/System.CommandLine.Tests/OptionTests.cs

@@ -373,8 +373,7 @@ public void Option_of_enum_can_limit_enum_members_as_valid_values()
         public void Option_of_T_fluent_APIs_return_Option_of_T()
         {
             Option<string> option = new Option<string>("--path")
-                .AcceptLegalFileNamesOnly()
-                .AcceptLegalFilePathsOnly();
+                .AcceptLegalFileNamesOnly();
 
             option.Should().BeOfType<Option<string>>();
         }

src/System.CommandLine.Tests/ParsingValidationTests.cs

@@ -582,9 +582,11 @@ public void LegalFilePathsOnly_rejects_command_arguments_containing_invalid_path
             [Fact]
             public void LegalFilePathsOnly_rejects_option_arguments_containing_invalid_path_characters()
             {
+                Option<string> option = new ("-x");
+                option.AcceptLegalFilePathsOnly();
                 var command = new Command("the-command")
                 {
-                    new Option<string>("-x").AcceptLegalFilePathsOnly()
+                    option
                 };
 
                 var invalidCharacter = Path.GetInvalidPathChars().First(c => c != '"');
@@ -620,9 +622,12 @@ public void LegalFilePathsOnly_accepts_command_arguments_containing_valid_path_c
             [Fact]
             public void LegalFilePathsOnly_accepts_option_arguments_containing_valid_path_characters()
             {
+                Option<string[]> option = new ("-x");
+                option.AcceptLegalFilePathsOnly();
+
                 var command = new Command("the-command")
                 {
-                    new Option<string[]>("-x").AcceptLegalFilePathsOnly()
+                    option
                 };
 
                 var validPathName = Directory.GetCurrentDirectory();

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

@@ -109,11 +109,7 @@ public void SetDefaultValueFactory(Func<T> defaultValueFactory) =>
         /// Configures the option to accept only values representing legal file paths.
         /// </summary>
         /// <returns>The configured option.</returns>
-        public Option<T> AcceptLegalFilePathsOnly()
-        {
-            _argument.AcceptLegalFilePathsOnly();
-            return this;
-        }
+        public void AcceptLegalFilePathsOnly() => _argument.AcceptLegalFilePathsOnly();
 
         /// <summary>
         /// Configures the option to accept only values representing legal file names.