QUrlQuery: improve defaultQuery{Value,Pair}Delimiter()

- constexpr
- noexcept
- return char16_t (this converts implicitly to QChar, but allows use
  elsewhere, too)

[ChangeLog][QtCore][QUrlQuery] The defaultQueryValueDelimiter() and
defaultQueryPairDelimiter() functions now return char16_t instead of
QChar.

Change-Id: I4662f832a89ae9f4a984ea9349b5e0e212a09c95
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

src/corelib/io/qurlquery.cpp

@@ -768,18 +768,22 @@ void QUrlQuery::removeAllQueryItems(const QString &key)
 }
 
 /*!
-    \fn QChar QUrlQuery::defaultQueryValueDelimiter()
+    \fn QUrlQuery::defaultQueryValueDelimiter()
     Returns the default character for separating keys from values in the query,
     an equal sign ("=").
 
+    \note Prior to Qt 6, this function returned QChar.
+
     \sa setQueryDelimiters(), queryValueDelimiter(), defaultQueryPairDelimiter()
 */
 
 /*!
-    \fn QChar QUrlQuery::defaultQueryPairDelimiter()
+    \fn QUrlQuery::defaultQueryPairDelimiter()
     Returns the default character for separating keys-value pairs from each
     other, an ampersand ("&").
 
+    \note Prior to Qt 6, this function returned QChar.
+
     \sa setQueryDelimiters(), queryPairDelimiter(), defaultQueryValueDelimiter()
 */
 

src/corelib/io/qurlquery.h

@@ -102,10 +102,8 @@ public:
     QStringList allQueryItemValues(const QString &key, QUrl::ComponentFormattingOptions encoding = QUrl::PrettyDecoded) const;
     void removeAllQueryItems(const QString &key);
 
-    static QChar defaultQueryValueDelimiter()
-    { return QChar(ushort('=')); }
-    static QChar defaultQueryPairDelimiter()
-    { return QChar(ushort('&')); }
+    static constexpr char16_t defaultQueryValueDelimiter() noexcept { return u'='; }
+    static constexpr char16_t defaultQueryPairDelimiter() noexcept { return u'&'; }
 
 private:
     friend class QUrl;