Move flag operator declarations into the corresponding namespace

That's the recommended way, and things break if this isn't done
uniformly everywhere.

src/lib/barcodedecoder.h

@@ -97,7 +97,7 @@ private:
     mutable std::unordered_map<qint64, Result> m_cache;
 };
 
-}
+Q_DECLARE_OPERATORS_FOR_FLAGS(BarcodeDecoder::BarcodeTypes)
 
-Q_DECLARE_OPERATORS_FOR_FLAGS(KItinerary::BarcodeDecoder::BarcodeTypes)
+}
 

src/lib/knowledgedb/countrydb.h

@@ -51,6 +51,7 @@ enum PowerPlugType : uint16_t {
 };
 
 Q_DECLARE_FLAGS(PowerPlugTypes, PowerPlugType)
+Q_DECLARE_OPERATORS_FOR_FLAGS(PowerPlugTypes)
 Q_FLAG_NS(PowerPlugTypes)
 
 /** Returns the power plugs out of @p plugs that won't fit into @p sockets. */
@@ -79,7 +80,6 @@ KITINERARY_EXPORT CountryId countryIdForUicCode(uint16_t uicCountryCode);
 }
 }
 
-Q_DECLARE_OPERATORS_FOR_FLAGS(KItinerary::KnowledgeDb::PowerPlugTypes)
 Q_DECLARE_METATYPE(KItinerary::KnowledgeDb::DrivingSide)
 Q_DECLARE_METATYPE(KItinerary::KnowledgeDb::PowerPlugTypes)
 

src/lib/pdf/pdfimage.h

@@ -78,8 +78,9 @@ private:
     QExplicitlySharedDataPointer<PdfImagePrivate> d;
 };
 
+Q_DECLARE_OPERATORS_FOR_FLAGS(PdfImage::LoadingHints)
+
 }
 
 Q_DECLARE_METATYPE(KItinerary::PdfImage)
-Q_DECLARE_OPERATORS_FOR_FLAGS(KItinerary::PdfImage::LoadingHints)