QCalendar: replace two overloads with one QAnyStringView function

The backend was already ported, so this is just about applying
QT_REMOVED_SINCE and updating the docs.

Change-Id: I2c78908deb9cdb3cee19ce8bc148ab3117c1ad9a
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>

src/corelib/compat/removed_api.cpp

@@ -145,6 +145,14 @@ int QOperatingSystemVersion::compare(const QOperatingSystemVersion &v1,
 
 #if QT_REMOVED_SINCE(6, 4)
 
+#include "qcalendar.h"
+
+QCalendar::QCalendar(QStringView name)
+    : QCalendar(QAnyStringView{name}) {}
+
+QCalendar::QCalendar(QLatin1String name)
+    : QCalendar(QAnyStringView{name}) {}
+
 #include "qversionnumber.h"
 
 QT_WARNING_PUSH

src/corelib/time/qcalendar.cpp

@@ -1169,8 +1169,7 @@ const QCalendarBackend *QCalendarBackend::gregorian()
 /*!
     \fn QCalendar::QCalendar()
     \fn QCalendar::QCalendar(QCalendar::System system)
-    \fn QCalendar::QCalendar(QLatin1String name)
-    \fn QCalendar::QCalendar(QStringView name)
+    \fn QCalendar::QCalendar(QAnyStringView name)
 
     Constructs a calendar object.
 
@@ -1180,6 +1179,9 @@ const QCalendarBackend *QCalendarBackend::gregorian()
     calendar being constructed by other means first. With no argument, the
     default constructor returns the Gregorian calendar.
 
+    \note In Qt versions before 6.4, the constructor by \a name accepted only
+    QStringView and QLatin1String, not QAnyStringView.
+
     \sa QCalendar, System, isValid()
 */
 
@@ -1213,13 +1215,7 @@ QCalendar::QCalendar(QCalendar::SystemId id)
     Q_ASSERT(!d_ptr || d_ptr->calendarId().index() == id.index());
 }
 
-QCalendar::QCalendar(QLatin1String name)
-    : d_ptr(QCalendarBackend::fromName(name))
-{
-    Q_ASSERT(!d_ptr || d_ptr->calendarId().isValid());
-}
-
-QCalendar::QCalendar(QStringView name)
+QCalendar::QCalendar(QAnyStringView name)
     : d_ptr(QCalendarBackend::fromName(name))
 {
     Q_ASSERT(!d_ptr || d_ptr->calendarId().isValid());

src/corelib/time/qcalendar.h

@@ -146,10 +146,11 @@ public:
 
     explicit QCalendar(); // Gregorian, optimised
     explicit QCalendar(System system);
-    // ### Qt 7: remove
+#if QT_REMOVED_SINCE(6, 4)
     explicit QCalendar(QLatin1String name);
-    // ### Qt 7: use QAnyStringView
     explicit QCalendar(QStringView name);
+#endif
+    explicit QCalendar(QAnyStringView name);
     explicit QCalendar(SystemId id);
 
     // QCalendar is a trivially copyable value type.