spelling: roslyn

Signed-off-by: Josh Soref <2119212+jsoref@users.noreply.github.com>

csharp/extractor/Semmle.Extraction.CSharp/SymbolExtensions.cs

@@ -10,7 +10,7 @@ namespace Semmle.Extraction.CSharp
 {
     /// <summary>
     /// An ITypeSymbol with nullability annotations.
-    /// Although a similar class has been implemented in Rolsyn,
+    /// Although a similar class has been implemented in Roslyn,
     /// https://github.com/dotnet/roslyn/blob/090e52e27c38ad8f1ea4d033114c2a107604ddaa/src/Compilers/CSharp/Portable/Symbols/TypeWithAnnotations.cs
     /// it is an internal struct that has not yet been exposed on the public interface.
     /// </summary>