Added a test for define/generic's interaction with marks.

Specifically, in the test, the bound name and the method name have marks on them
that are different from each other and from the original method names in the
enclosing generics group.

pkgs/racket-pkgs/racket-test/tests/generic/marked.rkt

@@ -0,0 +1,17 @@
+#lang racket/base
+
+(require racket/generic)
+
+(define-generics thing
+  (process thing stuff))
+
+(define-syntax-rule (define-thing name)
+  (struct name []
+    #:methods gen:thing
+    [(define-syntax-rule (define-super method)
+       (define/generic method process))
+     (define-super super)
+     (define (process x y)
+       (super y x))]))
+
+(define-thing type)

pkgs/racket-pkgs/racket-test/tests/generic/tests.rkt

@@ -18,5 +18,6 @@
          "empty-interface.rkt"
          "top-level.rkt"
          "pr13737.rkt"
+         "marked.rkt"
          "methods.rkt")