Traverse #%expression when looking for annotations.

Bug found by @mflatt's change to `syntax-parameterize`.

typed-racket-lib/typed-racket/typecheck/find-annotation.rkt

@@ -27,6 +27,7 @@
            #:with (expr ...) #'(cls.e ... body))
   (pattern (letrec-values cls:lv-clauses body)
            #:with (expr ...) #'(cls.e ... body))
+  (pattern (#%expression expr ...))
   (pattern (#%plain-app expr ...))
   (pattern (if expr ...))
   (pattern (with-continuation-mark expr ...))

typed-racket-lib/typed-racket/typecheck/tc-lambda-unit.rkt

@@ -31,6 +31,7 @@
 (define-syntax-class rebuild-let*
   #:literal-sets (kernel-literals)
   #:attributes (mapping flag-mapping)
+  (pattern (#%expression :rebuild-let*))
   (pattern (let-values ([(new-id) e:cl-rhs]) body:rebuild-let*)
            #:attr mapping (dict-set (attribute body.mapping) #'e.i #'new-id)
            #:attr flag-mapping (if (attribute e.cond)