[commands] Update Command documentation (NFC) (#3881)

Add reference to which VendorDep the class is included in.
Add missing OldCommands C++ Documentation (copied from Java).

wpilibNewCommands/src/main/native/include/frc2/command/TrapezoidProfileCommand.h

@@ -19,6 +19,8 @@ namespace frc2 {
  * A command that runs a TrapezoidProfile.  Useful for smoothly controlling
  * mechanism motion.
  *
+ * This class is provided by the NewCommands VendorDep
+ *
  * @see TrapezoidProfile
  */
 template <class Distance>