[ExamplePlugin] Update the 'expansion' witness for SendableExtensionMacro to

add the 'conformingTo' parameter.

(cherry picked from commit ec41bd6)

Author: hborla

Examples/Sources/ExamplePlugin/Macros.swift

@@ -91,8 +91,13 @@ public struct SendableExtensionMacro: ExtensionMacro {
     of node: AttributeSyntax,
     attachedTo: some DeclGroupSyntax,
     providingExtensionsOf type: some TypeSyntaxProtocol,
+    conformingTo protocols: [TypeSyntax],
     in context: some MacroExpansionContext
   ) throws -> [ExtensionDeclSyntax] {
+    if protocols.isEmpty {
+      return []
+    }
+
     let sendableExtension: DeclSyntax =
       """
       extension \(type.trimmed): Sendable {}