Doc: Move information about Qt Quick Controls to "Creating Components"

Move the topic up in the hierarchy. Will remove "Creating Screens" in
a follow-up commit.

Change-Id: I0de2bdc4706ab0cce13f5772006126b291e76b97
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>

doc/src/qtcreator-toc.qdoc

@@ -88,6 +88,11 @@
                 \li \l {Creating Qt Quick Projects}
                 \li \l {Qt Quick UI Forms}
                 \li \l {Editing QML Files in Design Mode}
+                \li \l {Creating Components}
+                    \list
+                        \li \l {Creating Buttons}
+                        \li \l {Creating Scalable Buttons and Borders}
+                    \endlist
                 \li \l {Managing Item Hierarchy}
                 \li \l {Specifying Item Properties}
                 \li \l {Editing PathView Properties}
@@ -99,10 +104,6 @@
                     \li \l{Managing C++ Backend Objects}
                 \endlist
                 \li \l {Adding States}
-                \li \l {Creating Components}
-                \li \l {Creating Buttons}
-                \li \l {Creating Scalable Buttons and Borders}
-                \li \l {Creating Screens}
                 \li \l {Browsing ISO 7000 Icons}
                 \li \l {Exporting Designs from Graphics Software}
                 \li \l {Using QML Modules with Plugins}