Sort global System usings before other global usings (#1004)

Src/CSharpier.Tests/FormattingTests/TestFiles/cs/UsingDirectives_SortsGlobalSystemToTop.expected.test

@@ -0,0 +1,4 @@
+global using System;
+global using System.Web;
+global using AWord;
+global using ZWord;

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

@@ -0,0 +1,4 @@
+global using ZWord;
+global using AWord;
+global using System.Web;
+global using System;

Src/CSharpier.Tests/FormattingTests/TestFiles/cs/UsingDirectives_SortsMixedCorrectly.expected.test

@@ -0,0 +1,8 @@
+global using System;
+global using System.Web;
+global using AWord;
+global using ZWord;
+using System;
+using System.Web;
+using AWord;
+using ZWord;

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

@@ -0,0 +1,8 @@
+global using ZWord;
+using ZWord;
+global using AWord;
+using AWord;
+global using System.Web;
+using System.Web;
+global using System;
+using System;

Src/CSharpier/SyntaxPrinter/UsingDirectives.cs

@@ -134,6 +134,7 @@ private static IEnumerable<List<UsingData>> GroupUsings(
         FormattingContext context
     )
     {
+        var globalSystemUsings = new List<UsingData>();
         var globalUsings = new List<UsingData>();
         var globalAliasUsings = new List<UsingData>();
         var systemUsings = new List<UsingData>();
@@ -187,9 +188,18 @@ FormattingContext context
 
                 if (usingDirective.GlobalKeyword.RawSyntaxKind() != SyntaxKind.None)
                 {
-                    (usingDirective.Alias is not null ? globalAliasUsings : globalUsings).Add(
-                        usingData
-                    );
+                    if (usingDirective.Alias is not null)
+                    {
+                        globalAliasUsings.Add(usingData);
+                    }
+                    else if (usingDirective.Name is not null && IsSystemName(usingDirective.Name))
+                    {
+                        globalSystemUsings.Add(usingData);
+                    }
+                    else
+                    {
+                        globalUsings.Add(usingData);
+                    }
                 }
                 else if (usingDirective.StaticKeyword.RawSyntaxKind() != SyntaxKind.None)
                 {
@@ -214,6 +224,7 @@ FormattingContext context
             }
         }
 
+        yield return globalSystemUsings.OrderBy(o => o.Using, Comparer).ToList();
         yield return globalUsings.OrderBy(o => o.Using, Comparer).ToList();
         yield return globalAliasUsings.OrderBy(o => o.Using, Comparer).ToList();
         yield return systemUsings.OrderBy(o => o.Using, Comparer).ToList();