Fix documentation of WebEngine Widgets Minimal Example

The printing of the source code was broken in commit 0fe0b13.
Make sure that the whole source code is printed. Also document the
commandLineUrlArgument() function.

Task-number: QTBUG-71691
Change-Id: I0044fb6508c712eab91e8d342624df5ea23e2fdc
Reviewed-by: Jüri Valdmann <[email protected]>
Reviewed-by: Leena Miettinen <[email protected]>

Author: kkoehne

examples/webenginewidgets/minimal/doc/src/minimal.qdoc

@@ -42,18 +42,24 @@
 
     \section1 The Code
 
+    We first define a \c commandLineUrlArgument function that returns the URL to open.
+    This is either the first positional argument given on the command line, or
+    \c https://www.qt.io as a fallback.
+
+    \quotefromfile webenginewidgets/minimal/main.cpp
+    \skipto #include
+
+    \printto int main
+
     In the \c main function we first set the Qt::AA_EnableHighDpiScaling.
     This lets the web view automatically scale on high-dpi displays.
 
     Next, we instantiate a QApplication and a QWebEngineView. The URL
-    to load is taken from the command-line in \c commandLineUrlArgument and
+    to load is taken from \c commandLineUrlArgument and
     loaded by calling \l QWebEngineView::setUrl. The view widget is
     given a reasonable default size, and shown.
     Finally, QApplication::exec() launches the main event loop.
 
-    \quotefromfile webenginewidgets/minimal/main.cpp
-    \skipto #include
-
     \printuntil }
 
     \section1 Requirements