[Generator] Refactor Format Type methods into TypeManager class (#19331)

First take at refactoring parts of the Generator:

1. RemoveArity() is now a string extension method with a test
2. FormatType, FormatTypeUsedIn, and part of PrimitiveType methods have
been moved into the TypeManager class.
3. TypeManager now has access to BindingTouch (similar to the other
Manager classes) so that it may call methods from NamespaceManager,
which also had to be made into a public property of BindingTouch vs
being passed through the Generator constructor.

---------

Co-authored-by: Manuel de la Pena <mandel@microsoft.com>
Co-authored-by: GitHub Actions Autoformatter <github-actions-autoformatter@xamarin.com>
Co-authored-by: Alex Soto <alex@alexsoto.me>

src/bgen/BindingTouch.cs

@@ -69,9 +69,11 @@ public class BindingTouch : IDisposable {
 
 	public MetadataLoadContext? universe;
 	public TypeManager? typeManager;
+	NamespaceManager? namespaceManager;
 	public TypeManager TypeManager => typeManager!;
 	public Frameworks? Frameworks;
 	public AttributeManager? AttributeManager;
+	public NamespaceManager NamespaceManager => namespaceManager!;
 	bool disposedValue;
 	readonly Dictionary<System.Type, Type> ikvm_type_lookup = new Dictionary<System.Type, Type> ();
 	internal Dictionary<System.Type, Type> IKVMTypeLookup {
@@ -535,13 +537,13 @@ int Main3 (string [] args)
 					strong_dictionaries.Add (t);
 			}
 
-			var nsManager = new NamespaceManager (
+			namespaceManager ??= new NamespaceManager (
 				this,
 				ns ?? firstApiDefinitionName,
 				skipSystemDrawing
 			);
 
-			var g = new Generator (this, nsManager, public_mode, external, debug, types.ToArray (), strong_dictionaries.ToArray ()) {
+			var g = new Generator (this, public_mode, external, debug, types.ToArray (), strong_dictionaries.ToArray ()) {
 				BaseDir = basedir ?? tmpdir,
 				ZeroCopyStrings = zero_copy,
 				InlineSelectors = inline_selectors ?? (CurrentPlatform != PlatformName.MacOSX),