Doc: Add info about Clang Format to "Specifying Code Style Settings"

If the Clang Format plugin is enabled, the settings look totally
different than currently described.

Updated screenshots.

Change-Id: I7b9a458329e539bb6140907a9c4ea9ec6c1acdba
Reviewed-by: Alessandro Portale <alessandro.portale@qt.io>
Reviewed-by: Ivan Donchevskii <ivan.donchevskii@qt.io>

doc/src/editors/creator-clangformat.qdocinc

@@ -28,7 +28,7 @@
 
     \section2 Automatic Formatting and Indentation
 
-    The experimental Clang Format plugin uses the
+    The Clang Format plugin uses the
     \l{https://clang.llvm.org/docs/LibFormat.html}{LibFormat}
     library for automatic formatting and indentation.
 

doc/src/projects/creator-only/creator-projects-settings-code-style.qdoc

@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2018 The Qt Company Ltd.
+** Copyright (C) 2019 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the Qt Creator documentation.
@@ -48,6 +48,16 @@
     switch between them. In addition, you can import and export code style
     settings.
 
+    \image qtcreator-projects-code-style.png "Code Style settings in Projects mode"
+
+    Alternatively, you can enable the Clang Format plugin to enforce
+    the code style specified in a \c {.clang-format} file. It uses the
+    \l{https://clang.llvm.org/docs/LibFormat.html}{LibFormat} library for
+    automatic code formatting and indentation. For more information, see
+    \l {Automatic Formatting and Indentation}.
+
+    \image qtcreator-code-style-clang-format.png "Clang Format Code Style settings in Projects mode"
+
     To specify global code style settings sets for C++ files, select
     \uicontrol {Tools > Options > C++}.