chore: remove two unused opened namespaces (#38079)

These were breaking after `lake shake --fix`: cf. #37857

Author: bryangingechen

Mathlib/CategoryTheory/Monoidal/Internal/Limits.lean

@@ -23,7 +23,7 @@ in particular `MonCat`, `SemiRingCat`, `RingCat`, and `AlgCat R`.)
 @[expose] public section
 
 
-open CategoryTheory Limits Monoidal MonoidalCategory
+open CategoryTheory Limits MonoidalCategory
 
 universe v u w
 

Mathlib/CategoryTheory/Monoidal/Widesubcategory.lean

@@ -27,7 +27,7 @@ them to construct monoidal, braided, and symmetric structures on
 
 namespace CategoryTheory
 
-open scoped MonoidalCategory ComonObj
+open scoped MonoidalCategory
 
 variable {C : Type*} [Category* C] (P : MorphismProperty C) [MonoidalCategory C]