Get stackalloc array initializers formatting consistently with other …

Src/CSharpier.Core/CSharp/SyntaxPrinter/RightHandSide.cs

@@ -126,7 +126,7 @@ or ConditionalExpressionSyntax
             or InterpolatedStringExpressionSyntax
             or IsPatternExpressionSyntax
             or LiteralExpressionSyntax
-            or StackAllocArrayCreationExpressionSyntax
+            or StackAllocArrayCreationExpressionSyntax { Initializer: null }
             or QueryExpressionSyntax => Layout.BreakAfterOperator,
             _ => Layout.Fluid,
         };

Src/CSharpier.Core/CSharp/SyntaxPrinter/SyntaxNodePrinters/ArrayCreationExpression.cs

@@ -11,7 +11,7 @@ public static Doc Print(ArrayCreationExpressionSyntax node, PrintingContext cont
             Token.PrintWithSuffix(node.NewKeyword, " ", context),
             Node.Print(node.Type, context),
             node.Initializer != null
-                ? Doc.Concat(Doc.Line, Node.Print(node.Initializer, context))
+                ? Doc.Concat(Doc.Line, InitializerExpression.Print(node.Initializer, context))
                 : Doc.Null
         );
     }

Src/CSharpier.Core/CSharp/SyntaxPrinter/SyntaxNodePrinters/InitializerExpression.cs

@@ -58,6 +58,7 @@ is not SyntaxKind.ComplexElementInitializerExpression
                 is not (
                     ObjectCreationExpressionSyntax
                     or ArrayCreationExpressionSyntax
+                    or StackAllocArrayCreationExpressionSyntax
                     or ImplicitArrayCreationExpressionSyntax
                     or ImplicitObjectCreationExpressionSyntax
                 )

Src/CSharpier.Core/CSharp/SyntaxPrinter/SyntaxNodePrinters/StackAllocArrayCreationExpression.cs

@@ -7,12 +7,12 @@ internal static class StackAllocArrayCreationExpression
 {
     public static Doc Print(StackAllocArrayCreationExpressionSyntax node, PrintingContext context)
     {
-        return Doc.Concat(
+        return Doc.Group(
             Token.PrintWithSuffix(node.StackAllocKeyword, " ", context),
             Node.Print(node.Type, context),
             node.Initializer != null
-                ? Doc.Concat(" ", InitializerExpression.Print(node.Initializer, context))
-                : string.Empty
+                ? Doc.Concat(Doc.Line, InitializerExpression.Print(node.Initializer, context))
+                : Doc.Null
         );
     }
 }

Src/CSharpier.Tests/FormattingTests/TestFiles/cs/StackAllocArrayCreationExpressions.test

@@ -1,10 +1,14 @@
-class ClassName
+Span<int> a = stackalloc int[3];
+Span<int> a = stackalloc int[3] { 1, 2, 3 };
+Span<int> a = stackalloc int[] { 1, 2, 3 };
+Span<int> a = stackalloc[] { 1, 2, 3 };
+
+Span<byte> someLongName_________________________ =
+    stackalloc byte[JsonConstants.MaximumEscapedDateTimeOffsetParseLength];
+
+Span<int> metatable = stackalloc int[]
 {
-    void MethodName()
-    {
-        Span<int> a = stackalloc int[3];
-        Span<int> a = stackalloc int[3] { 1, 2, 3 };
-        Span<int> a = stackalloc int[] { 1, 2, 3 };
-        Span<int> a = stackalloc[] { 1, 2, 3 };
-    }
-}
+    00000000000000000000000001,
+    00000000000000000000000002,
+    00000000000000000000000003,
+};