[mlir] NFC: tiny fix in comment.

[csigg]

Add another one.

[mehdi_amini]

(Feel free to just push directly this kind of fixes)

mlir/include/mlir/IR/Types.h

public:
 
   // Support type casting Type to itself.
   static bool classof(Type) { return true; }
 
   /// Return a unique identifier for the concrete type. This is used to support
   /// dynamic type casting.
   TypeID getTypeID() { return impl->getAbstractType().getTypeID(); }
 
-  /// Return the LLVMContext in which this type was uniqued.
+  /// Return the MLIRContext in which this type was uniqued.
   MLIRContext *getContext() const;
 
   /// Get the dialect this type is registered to.
   Dialect &getDialect() const;
 
   // Convenience predicates.  This is only for floating point types,
   // derived types should use isa/dyn_cast.
   bool isIndex();