Adds ValueFormatter to ProgressBar

test/Spectre.Console.Tests/Expectations/Widgets/ProgressBar/Formatted.Output.verified.txt

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+━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 9,000

test/Spectre.Console.Tests/Expectations/Widgets/ProgressBar/Render.Output.verified.txt

@@ -0,0 +1 @@
+━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 9000

test/Spectre.Console.Tests/Unit/Widgets/ProgressBarTests.cs

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+namespace Spectre.Console.Tests.Unit;
+
+[UsesVerify]
+[ExpectationPath("Widgets/ProgressBar")]
+public class ProgressBarTests
+{
+    [Fact]
+    [Expectation("Render")]
+    public async Task Should_Render_Correctly()
+    {
+        // Given
+        var console = new TestConsole();
+
+        var bar = new ProgressBar()
+        {
+            Width = 60,
+            Value = 9000,
+            MaxValue = 9000,
+            ShowValue = true,
+        };
+
+        // When
+        console.Write(bar);
+
+        // Then
+        await Verifier.Verify(console.Output);
+    }
+
+    [Fact]
+    [Expectation("Formatted")]
+    public async Task Should_Render_ValueFormatted()
+    {
+        // Given
+        var console = new TestConsole();
+
+        var bar = new ProgressBar()
+        {
+            Width = 60,
+            Value = 9000,
+            MaxValue = 9000,
+            ShowValue = true,
+            ValueFormatter = (value, _) => value.ToString("N0"),
+        };
+
+        // When
+        console.Write(bar);
+
+        // Then
+        await Verifier.Verify(console.Output);
+    }
+}