Doc: Promote the Multieffect QML type page

This QML module, part of the Qt Quick Effects submodule, is not very
visible across the Qt Quick pages. Also, inform that this QML type
is the successor to the Qt Graphical Effects from Qt 5.

Fixes: QTBUG-111481
Change-Id: I933bcc196a292a08135bcf77b397b5f7ff5d4827
Reviewed-by: Kaj Grönholm <kaj.gronholm@qt.io>
(cherry picked from commit da4e62d07a)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

src/effects/qquickmultieffect.cpp

@@ -31,11 +31,13 @@ Q_LOGGING_CATEGORY(lcQuickEffect, "qt.quick.effects")
     \ingroup qtquick-effects
     \brief Applies post-processing effect to an item.
 
-    The MultiEffect type applies a post-processing effect to \l source item.
-    Compared to \c {Qt Graphical Effects} module, MultiEffect combines multiple
-    effects (blur, shadow, colorization etc.) into a single item and shader which
-    makes it better for multiple effects. There are several shader variations
-    and the most optimal one gets selected based on the features used.
+    The MultiEffect type, the successor to the deprecated Qt Graphical Effects
+    from Qt 5, applies a post-processing effect to the \l source item. Compared
+    to the Qt Graphical Effects module, MultiEffect combines multiple
+    effects (blur, shadow, colorization etc.) into a single item and shader
+    which makes it better for multiple effects. There are several shader
+    variations and the most optimal one gets selected based on the features
+    used.
 
     MultiEffect is designed specifically for most common effects and can be easily animated.
     If the MultiEffect doesn't contain the effect you need, consider implementing a custom

src/quick/doc/src/concepts/effects/topic.qdoc

@@ -15,6 +15,9 @@ a useful way to subtly communicate to the user (for example, which visual
 item is active, or how focus is being transferred).  Over-use of visual
 effects can actually detract from the user-experience.
 
+For more information about applying post-processing effects, such as blur, drop
+shadow, or colarize, to an \l Item, see the \l MultiEffect QML type.
+
 \section1 Visual Transformation
 
 Visual objects can be transformed.  For example, they can be scaled or rotated.

src/quick/doc/src/qmltypereference.qdoc

@@ -17,11 +17,11 @@ import QtQuick
 \endqml
 
 Visit the \l {Qt Quick} module documentation for more
-information about the concepts which are central to \c QtQuick.
+information about the concepts that are central to \c QtQuick.
 
 \section1 Submodules
 
-    Qt Quick includes several submodules which contain additional types.
+    Qt Quick includes several submodules that contain additional types:
 
     \list
     \li \l{Qt Quick Local Storage QML Types}{Local Storage} - a submodule
@@ -33,6 +33,8 @@ information about the concepts which are central to \c QtQuick.
     \li \l{Qt Quick Layouts QML Types}{Layouts} - contains types that are used
     to arrange items in the user interface
     \li \l{Qt Quick Test QML Types}{Tests} - types for testing QML applications.
+    \li \l{Qt Quick Effects QML Types}{Effects} - provides types for applying
+    one or more simple graphical effects to Qt Quick items.
     \endlist
 
 \target value-types

src/quick/doc/src/qtquick.qdoc

@@ -61,8 +61,10 @@ shader effects.
            {States, Transitions And Animations}
     \li \l {Important Concepts In Qt Quick - Data - Models, Views and data Storage}
            {Data - Models, Views and Data Storage}
-    \li \l {Important Concepts In Qt Quick - Graphical Effects}{Particles And
-           Graphical Effects}
+    \li \list \l {Important Concepts In Qt Quick - Graphical Effects}
+           {Particles And Graphical Effects}
+       \li \l MultiEffect
+    \endlist
     \li \l {Important Concepts In Qt Quick - Convenience Types}
            {Convenience Types}
 \endlist