Don't add newlines at the start of implicit expressions in on type formatting (#12489)

Fixes #12481

Author: davidwengier

src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Formatting/Passes/CSharpOnTypeFormattingPass.cs

@@ -339,7 +339,14 @@ private static void CleanupSourceMappingStart(FormattingContext context, LinePos
 
         var text = context.SourceText;
         var sourceMappingSpan = text.GetTextSpan(sourceMappingRange);
-        if (!ShouldFormat(context, sourceMappingSpan, allowImplicitStatements: false, out var owner))
+        if (!ShouldFormat(context,
+            sourceMappingSpan,
+            new ShouldFormatOptions(
+                AllowImplicitStatements: false,
+                AllowImplicitExpressions: false,
+                AllowSingleLineExplicitExpressions: true,
+                IsLineRequest: false),
+            out var owner))
         {
             // We don't want to run cleanup on this range.
             return;

src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/Formatting_NetFx/FormattingTestBase.cs

@@ -166,7 +166,7 @@ private protected async Task RunOnTypeFormattingTestAsync(
             filePathService, new TestDocumentContextFactory(), LoggerFactory);
         var languageKind = codeDocument.GetLanguageKind(positionAfterTrigger, rightAssociative: false);
 
-        var formattingService = await TestRazorFormattingService.CreateWithFullSupportAsync(LoggerFactory, TestOutputHelper, codeDocument, razorLSPOptions, languageServerFeatureOptions);
+        var formattingService = await TestRazorFormattingService.CreateWithFullSupportAsync(LoggerFactory, TestOutputHelper, codeDocument, razorLSPOptions, languageServerFeatureOptions, debugAssertsEnabled: true);
         var options = new FormattingOptions()
         {
             TabSize = tabSize,

src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/Formatting_NetFx/OnTypeFormattingTest.cs

@@ -18,6 +18,44 @@ namespace Microsoft.AspNetCore.Razor.LanguageServer.Formatting;
 public class OnTypeFormattingTest(FormattingTestContext context, HtmlFormattingFixture fixture, ITestOutputHelper testOutput)
     : FormattingTestBase(context, fixture.Service, testOutput), IClassFixture<FormattingTestContext>
 {
+    [FormattingTestFact]
+    public async Task FormatsElseCloseBrace()
+    {
+        await RunOnTypeFormattingTestAsync(
+            input: """
+                    @page "/"
+
+                    @if (true)
+                    {
+                        <option value="@streetKind">@streetKind</option>
+                    }
+                    else {
+                        <input />
+                    }$$
+
+                    @code {
+                        private string? streetKind;
+                    }
+                    """,
+            expected: """
+                    @page "/"
+
+                    @if (true)
+                    {
+                        <option value="@streetKind">@streetKind</option>
+                    }
+                    else
+                    {
+                        <input />
+                    }
+
+                    @code {
+                        private string? streetKind;
+                    }
+                    """,
+            triggerCharacter: '}');
+    }
+
     [FormattingTestFact]
     public async Task FormatsIfStatementInComponent()
     {

src/Razor/test/Microsoft.VisualStudio.LanguageServices.Razor.Test/Cohost/Formatting/FormattingTestBase.cs

@@ -123,7 +123,9 @@ private protected async Task RunOnTypeFormattingTestAsync(
         var position = inputText.GetPosition(input.Position);
 
         var formattingService = (RazorFormattingService)OOPExportProvider.GetExportedValue<IRazorFormattingService>();
-        formattingService.GetTestAccessor().SetFormattingLoggerFactory(new TestFormattingLoggerFactory(TestOutputHelper));
+        var accessor = formattingService.GetTestAccessor();
+        accessor.SetDebugAssertsEnabled(debugAssertsEnabled: true);
+        accessor.SetFormattingLoggerFactory(new TestFormattingLoggerFactory(TestOutputHelper));
 
         var generatedHtml = await RemoteServiceInvoker.TryInvokeAsync<IRemoteHtmlDocumentService, string?>(document.Project.Solution,
             (service, solutionInfo, ct) => service.GetHtmlDocumentTextAsync(solutionInfo, document.Id, ct),