Fix source generator exceptions appearing when use "@+internal keyword" as type or namespace name in C# script

modules/mono/editor/Godot.NET.Sdk/Godot.SourceGenerators.Tests/KeywordClassNameAndNamespaceTest.cs

@@ -0,0 +1,15 @@
+using Xunit;
+
+namespace Godot.SourceGenerators.Tests;
+
+public class KeywordClassAndNamespaceTest
+{
+    [Fact]
+    public async void GenerateScriptMethodsTest()
+    {
+        await CSharpSourceGeneratorVerifier<ScriptMethodsGenerator>.Verify(
+            "KeywordClassNameAndNamespace.cs",
+            "namespace.class_ScriptMethods.generated.cs"
+        );
+    }
+}