libhidpp: hidpp20: Change LogitechInternal error to NotAllowed

There has been some confusion about error value 5 but feature specs that refer
to it generally use NOT_ALLOWED.

Deprecate the LogitechInternal identifier but keep it around for now.

src/libhidpp/hidpp20/Error.cpp

@@ -45,8 +45,8 @@ const char *Error::what () const noexcept
 		return "Out of range";
 	case HWError:
 		return "Hardware error";
-	case LogitechInternal:
-		return "Logitech internal";
+	case NotAllowed:
+		return "Not allowed";
 	case InvalidFeatureIndex:
 		return "Invalid feature index";
 	case InvalidFunctionID:

src/libhidpp/hidpp20/Error.h

@@ -36,7 +36,8 @@ class Error: public std::exception
 		InvalidArgument = 2,
 		OutOfRange = 3,
 		HWError = 4,
-		LogitechInternal = 5,
+		NotAllowed = 5,
+		LogitechInternal [[deprecated]] = NotAllowed,
 		InvalidFeatureIndex = 6,
 		InvalidFunctionID = 7,
 		Busy = 8,