Doc: Fix documentation warnings

These warnings slipped in during a time period where documentation
testing in the CI was disabled.

src/network/kernel/qhostinfo.cpp:254: (qdoc) warning: clang couldn't
    find function when parsing \fn template<typename Functor>
    int QHostInfo::lookupHost(const QString &name, Functor functor)

src/widgets/widgets/qcheckbox.cpp:102: (qdoc) warning: clang couldn't
    find function when parsing
    \fn void QCheckBox::stateChanged(Qt::CheckState state)

src/corelib/kernel/qcoreapplication.cpp:2769: (qdoc) warning: clang
    couldn't find function when parsing
    \fn template<typename Functor> void
        QCoreApplication::requestPermission(
        const QPermission &permission, Functor functor)

src/corelib/serialization/qxmlstream.cpp:3806: (qdoc) warning: clang
    couldn't find function when parsing
    \fn bool QXmlStreamAttributes::hasAttribute(
        const QString &qualifiedName) const

src/corelib/text/qtliterals.qdoc:11: (qdoc) warning: Multiple topic
    commands found in comment: \namespace and \headerfile.

Change-Id: I38c605f358dbca1ef3e2bfe20a6424f7a4d44b4a
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
(cherry picked from commit 37dc52d4f24c216811cf14ceb8aeaa13766b249d)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

src/corelib/kernel/qcoreapplication.cpp

@@ -2768,7 +2768,7 @@ Qt::PermissionStatus QCoreApplication::checkPermission(const QPermission &permis
 
 /*!
     \fn template<typename Functor> void QCoreApplication::requestPermission(
-        const QPermission &permission, Functor functor)
+        const QPermission &permission, Functor &&functor)
 
     Requests the given \a permission.
 

src/corelib/serialization/qxmlstream.cpp

@@ -3829,8 +3829,7 @@ void QXmlStreamWriter::writeCurrentToken(const QXmlStreamReader &reader)
 }
 
 /*!
- \fn bool QXmlStreamAttributes::hasAttribute(const QString &qualifiedName) const
- \since 4.5
+ \fn bool QXmlStreamAttributes::hasAttribute(QAnyStringView qualifiedName) const
 
  Returns \c true if this QXmlStreamAttributes has an attribute whose
  qualified name is \a qualifiedName; otherwise returns \c false.
@@ -3844,16 +3843,9 @@ void QXmlStreamWriter::writeCurrentToken(const QXmlStreamReader &reader)
 */
 
 /*!
- \fn bool QXmlStreamAttributes::hasAttribute(QLatin1StringView qualifiedName) const
+ \fn bool QXmlStreamAttributes::hasAttribute(QAnyStringView namespaceUri,
+                                             QAnyStringView name) const
  \overload
- \since 4.5
-*/
-
-/*!
- \fn bool QXmlStreamAttributes::hasAttribute(const QString &namespaceUri,
-                                             const QString &name) const
- \overload
- \since 4.5
 
  Returns \c true if this QXmlStreamAttributes has an attribute whose
  namespace URI and name correspond to \a namespaceUri and \a name;

src/corelib/text/qtliterals.qdoc

@@ -11,7 +11,7 @@
 /*!
     \namespace Qt::Literals
     \inmodule QtCore
-    \headerfile QtLiterals
+    \inheaderfile QtLiterals
 
     \brief The Literals inline namespace declares literal operators for Qt types.
 */
@@ -19,7 +19,7 @@
 /*!
     \namespace Qt::Literals::StringLiterals
     \inmodule QtCore
-    \headerfile QStringLiterals
+    \inheaderfile QStringLiterals
 
     \brief The StringLiterals namespace declares string literal operators
     for Qt types.

src/network/kernel/qhostinfo.cpp

@@ -262,7 +262,7 @@ int QHostInfo::lookupHost(const QString &name, QObject *receiver, const char *me
 */
 
 /*!
-    \fn template<typename Functor> int QHostInfo::lookupHost(const QString &name, Functor functor)
+    \fn template<typename Functor> int QHostInfo::lookupHost(const QString &name, Functor &&functor)
 
     \since 5.9
 

src/widgets/widgets/qcheckbox.cpp

@@ -91,6 +91,7 @@ public:
 
 /*!
     \fn void QCheckBox::stateChanged(int state)
+    //! Qt 7: \fn void QCheckBox::stateChanged(Qt::CheckState state)
 
     This signal is emitted whenever the checkbox's state changes, i.e.,
     whenever the user checks or unchecks it.