Doc: Fix documentation warnings for Qt GUI

* Drop deprecation warnings for now-dropped items
* Use the 'qt6' define and a new \nothing doc macro to conditionally
  document items on Qt 6
* Add a custom module header for docs that pulls in also Vulkan headers
* Add \internal command for internal classes/functions
* Move QtGUI-related code snippets from widgets to gui docs

Change-Id: Ieb386b96631a49568d09059906d307c45c01d93a
Reviewed-by: Paul Wicking <paul.wicking@qt.io>

3 files changed, 13 insertions, 5 deletions

diff --git a/src/gui/painting/qcolor.cpp b/src/gui/painting/qcolor.cpp
index 6b666435e6..89a75d8b2b 100644
--- a/src/gui/painting/qcolor.cpp
+++ b/src/gui/painting/qcolor.cpp
@@ -843,11 +843,15 @@ QColor::QColor(Spec spec) noexcept
 
 #if QT_VERSION < QT_VERSION_CHECK(6,0,0)
 /*!
+\if !defined(qt6)
     \fn QColor::QColor(const QColor &color)
 
     Constructs a color that is a copy of \a color.
 
     \sa isValid()
+\else
+    \nothing
+\endif
 */
 #endif
 
diff --git a/src/gui/painting/qpaintengine_raster.cpp b/src/gui/painting/qpaintengine_raster.cpp
index 5c21f22df1..f34b4bb9a2 100644
--- a/src/gui/painting/qpaintengine_raster.cpp
+++ b/src/gui/painting/qpaintengine_raster.cpp
@@ -339,7 +339,7 @@ QRasterPaintEnginePrivate::QRasterPaintEnginePrivate() :
     \sa QPaintEngine
 */
 
-/*!
+/*
     \fn QPaintEngine::Type QRasterPaintEngine::type() const
     \reimp
 */
@@ -4909,7 +4909,7 @@ static void drawEllipse_midpoint_i(const QRect &rect, const QRect &clip,
     }
 }
 
-/*!
+/*
     \fn void QRasterPaintEngine::drawPoints(const QPoint *points, int pointCount)
     \overload
     \reimp
diff --git a/src/gui/painting/qrangecollection.cpp b/src/gui/painting/qrangecollection.cpp
index 5fd4ebaa4b..8f212a1b08 100644
--- a/src/gui/painting/qrangecollection.cpp
+++ b/src/gui/painting/qrangecollection.cpp
@@ -96,7 +96,7 @@ QRangeCollection::~QRangeCollection()
 }
 
 /*!
-    Inserts a single number into the collection.
+    Inserts a single number \a pageNumber into the collection.
  */
 void QRangeCollection::addPage(int pageNumber)
 {
@@ -110,7 +110,7 @@ void QRangeCollection::addPage(int pageNumber)
 }
 
 /*!
-    Inserts a range into the collection.
+    Inserts a range specified with \a from and \a to into the collection.
  */
 void QRangeCollection::addRange(int from, int to)
 {
@@ -146,12 +146,14 @@ void QRangeCollection::clear()
 }
 
 /*!
-    Constructs the range collection from a string representation.
+    Constructs the range collection from a string representation of \a ranges.
 
     \code
     QPrinter printer;
     printer->rangeCollection()->parse("1-3,6-7");
     \endcode
+
+    Returns \c true on success.
  */
 bool QRangeCollection::parse(const QString &ranges)
 {
@@ -233,6 +235,8 @@ QString QRangeCollection::toString() const
 }
 
 /*!
+    \fn bool QRangeCollection::contains(const int pageNumber) const
+
     Returns \c true if the collection contains an occurrence
     or a bounding range of \a pageNumber; otherwise returns
     \c false.