Doc: Clear a number of documentation warnings

QDoc gets confused about the contents of doc_src_plugins.qdoc,
mistaking some of its code for QDoc commands.

To work around this problem, change the file to be a qdoc
include file, wrap the code blocks with \badcode, and
refer to them using \include.

Using \badcode will also turn off code highlighting and
autolinking, something that is not desired for these code
snippets.

Change-Id: I6c3b65ef098ec6f6f06892d78a3abb38e0d28ca3
Reviewed-by: Leena Miettinen <riitta-leena.miettinen@digia.com>

doc/src/widgets/doc_src_plugins.qdocinc

@@ -17,11 +17,14 @@
 ****************************************************************************/
 
 //! [0]
+\badcode
 otool -L /Developer/Applications/Qt/plugins/designer/libqwt_designer_plugin.dylib
+\endcode
 //! [0]
 
 
 //! [1]
+\badcode
 /Developer/Applications/Qt/plugins/designer/libqwt_designer_plugin.dylib:
 	libqwt_designer_plugin.dylib (compatibility version 0.0.0, current version 0.0.0)
 	libqwt.5.dylib (compatibility version 5.2.0, current version 5.2.1)
@@ -33,14 +36,18 @@ otool -L /Developer/Applications/Qt/plugins/designer/libqwt_designer_plugin.dyli
 	/usr/lib/libstdc++.6.dylib (compatibility version 7.0.0, current version 7.9.0)
 	/usr/lib/libgcc_s.1.dylib (compatibility version 1.0.0, current version 438.0.0)
 	/usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 125.0.1)
+\endcode
 //! [1]
 
 //! [2]
+\badcode
 otool -L /usr/local/qwt-5.2.1/lib/libqwt.5.dylib
+\endcode
 //! [2]
 
 
 //! [3]
+\badcode
 /usr/local/qwt-5.2.1/lib/libqwt.5.dylib:
 	libqwt.5.dylib (compatibility version 5.2.0, current version 5.2.1)
 	QtGui.framework/Versions/4/QtGui (compatibility version 4.6.0, current version 4.6.2)
@@ -48,18 +55,22 @@ otool -L /usr/local/qwt-5.2.1/lib/libqwt.5.dylib
 	/usr/lib/libstdc++.6.dylib (compatibility version 7.0.0, current version 7.9.0)
 	/usr/lib/libgcc_s.1.dylib (compatibility version 1.0.0, current version 438.0.0)
 	/usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 125.0.1)
+\endcode
 //! [3]
 
 
 //! [4]
+\badcode
 sudo cp /Developer/Applications/Qt/plugins/designer/libqwt_designer_plugin.dylib \
         /Developer/Applications/Qt/Qt\ Creator.app/Contents/MacOS/designer
 sudo cp -R /usr/local/qwt-5.2.1/lib/*  \
         /Developer/Applications/Qt/Qt\ Creator.app/Contents/Frameworks/
+\endcode
 //! [4]
 
 
 //! [5]
+\badcode
 cd /Developer/Applications/Qt/Qt\ Creator.app/Contents/MacOS/designer
 sudo install_name_tool -change
     QtCore.framework/Versions/4/QtCore \
@@ -90,4 +101,6 @@ sudo install_name_tool -change \
     QtGui.framework/Versions/4/QtGui \
     @executable_path/../Frameworks/libQtGui.4.dylib \
     libqwt.5.2.1.dylib
+\endcode
 //! [5]
+

doc/src/widgets/qtdesigner-plugins.qdoc

@@ -85,13 +85,13 @@
         \li To check the paths used in the Qwt library, enter the following
             \c otool command:
 
-            \snippet doc_src_plugins.qdoc 0
+            \include doc_src_plugins.qdocinc 0
 
             The output for Qwt 5.2.1 indicates that the plugin uses Qt core
             libraries (QtDesigner, QtScript, QtXml, QtGui and QtCore) and
             libqwt.5.dylib:
 
-            \snippet doc_src_plugins.qdoc 1
+            \include doc_src_plugins.qdocinc 1
 
 
         \li You must copy the \QD plugin and the Qwt library files to the
@@ -108,21 +108,21 @@
 
             Enter the following commands:
 
-            \snippet doc_src_plugins.qdoc 4
+            \include doc_src_plugins.qdocinc 4
 
         \li Enter the following \c otool command to check the libraries that are
             used by the Qwt library:
 
-            \snippet doc_src_plugins.qdoc 2
+            \include doc_src_plugins.qdocinc 2
 
             The command returns the following output:
 
-            \snippet doc_src_plugins.qdoc 3
+            \include doc_src_plugins.qdocinc 3
 
         \li Enter the following \c install_name_tool command to fix the
             references of the libraries:
 
-            \snippet doc_src_plugins.qdoc 5
+            \include doc_src_plugins.qdocinc 5
 
     \endlist