ClangFormat: Introduce check to format code instead of indenting

Ctrl+I with the new check will reformat the selected code or
the current line instead.

Change-Id: Ia5a72c4a09621034d0dfe463f669fe1ca36b0b5f
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@qt.io>
Reviewed-by: Marco Bubke <marco.bubke@qt.io>

src/plugins/clangformat/clangformatindenter.h

@@ -38,6 +38,7 @@ public:
     Utils::optional<TextEditor::TabSettings> tabSettings() const override;
 
 private:
+    bool formatCodeInsteadOfIndent() const override;
     clang::format::FormatStyle styleForFile() const override;
 };