[Generator] The generator creates not compilable code when a selector has the word Handle in it.

[mandel-macaque]

Given the following example binding:

        [NoWatch, NoTV, Mac (14,0), iOS (17,0), MacCatalyst (17,0)]
	[Protocol]
	[BaseType (typeof(NSObject))]
	interface ASCredentialIdentity {

		[Abstract]
		[Export ("serviceIdentifier", ArgumentSemantic.Strong)]
		ASCredentialServiceIdentifier ServiceIdentifier { get; }

		[Abstract]
		[Export ("user")]
		string User { get; }

		[Abstract]
		[NullAllowed, Export ("recordIdentifier")]
		string RecordIdentifier { get; }

		[Abstract]
		[Export ("rank")]
		nint Rank { get; set; }
	}
        
        [NoWatch, NoTV, Mac (14,0), iOS (17,0), MacCatalyst (17,0)]
	[BaseType (typeof (NSObject))]
	[DisableDefaultCtor]
	interface ASPasskeyCredentialIdentity : NSCopying, NSSecureCoding, ASCredentialIdentity {
		[Export ("initWithRelyingPartyIdentifier:userName:credentialID:userHandle:recordIdentifier:")]
		NativeHandle Constructor (string relyingPartyIdentifier, string userName, NSData credentialID, NSData userHandle, [NullAllowed] string recordIdentifier);

		[Static]
		[Export ("identityWithRelyingPartyIdentifier:userName:credentialID:userHandle:recordIdentifier:")]
		ASPasskeyCredentialIdentity CreateIdentity (string relyingPartyIdentifier, string userName, NSData credentialID, NSData userHandle, [NullAllowed] string recordIdentifier);

		[Export ("relyingPartyIdentifier")]
		string RelyingPartyIdentifier { get; }

		[Export ("userName")]
		string UserName { get; }

		[Export ("credentialID", ArgumentSemantic.Copy)]
		NSData CredentialID { get; }

		[Export ("userHandle", ArgumentSemantic.Copy)]
		NSData UserHandle { get; }

		[NullAllowed, Export ("recordIdentifier")]
		new string RecordIdentifier { get; }

		[Export ("rank")]
		new nint Rank { get; set; }
	}

The generator will create two private fields in the generated class that use the same name resulting in the following error:

build/dotnet/macos/generated-sources/AuthenticationServices/ASPasskeyCredentialIdentity.g.cs(90,16): error CS0102: The type 'ASPasskeyCredentialIdentity' already contains a definition for 'selUserHandle'
make[1]: *** [build/dotnet/macos/ref/Microsoft.macOS.dll] Error 1
make[1]: *** Waiting for unfinished jobs....
^Cmake[1]: *** [build/dotnet/ios/ref/Microsoft.iOS.dll] Deleting file `build/dotnet/ios/ref/Microsoft.iOS.xml'
make[1]: *** [build/dotnet/ios/ref/Microsoft.iOS.dll] Deleting file `build/dotnet/ios/64/Microsoft.iOS.pdb'
make[1]: *** [build/dotnet/ios/ref/Microsoft.iOS.dll] Deleting file `build/dotnet/ios/64/Microsoft.iOS.dll'
make[1]: *** [build/dotnet/ios/ref/Microsoft.iOS.dll] Interrupt: 2
make[1]: *** Deleting intermediate file `build/tvos/reference/Xamarin.TVOS.dll'
make[1]: *** Deleting intermediate file `build/watch/reference/MonoTouch.NUnitLite.dll'
make[1]: *** Deleting intermediate file `build/watch/reference/Xamarin.WatchOS.dll'
make: *** [all-recurse] Interrupt: 2

The reason for this is that we have the word handle and the ned of the selector form the property. Because we do not keep track of the variable names in the scope, this results a duplicated variable name. There are 2 ways to fix this:

1. Simplest way is to perform the same code we have now but add a prefix to the word handle that we know will probably not happened in a selector from Apple.
2. Make the generator aware of the variables in the current context, and if a variable has already been used in the same context, add a postfix of some kind.

Approach 1 is easier for several reasons:

1. The code to change is minimal.
2. We do have manual code (in the Foundation directory) that uses the knowledge of the selector naming convention used by the Generator. Using approach 2 in which we add a postfix only if we found a variable with the same name makes the manual code much harder to write and fragile.