Deprecate method retrieval in module

Mark method as deprecated to discourage direct use.

Author: shoumikhin

extension/module/module.h

@@ -206,6 +206,8 @@ class Module {
   }
 
   /**
+   * DEPRECATED: Module manages each Method exclusively.
+   *
    * Get a method by it's name. Not recommended to use this method directly as
    * an end user. It's exposed to allow for composability of module in apis that
    * operate on method.
@@ -215,7 +217,7 @@ class Module {
    * @returns A Result object containing either a pointer to the requested
    *          method or an error to indicate failure.
    */
-  ET_NODISCARD runtime::Result<Method*> method(const std::string& method_name);
+  ET_DEPRECATED ET_NODISCARD runtime::Result<Method*> method(const std::string& method_name);
 
   /**
    * Load the 'forward' method from the program and set up memory management if