DiffEditor: Modernize

* Use member init
* Use nullptr
* Use range-for
* omit QLatin1{String|Char} where possible

Change-Id: Ib231b747cdd9073b3d4fc6779b8e0afb2b404a31
Reviewed-by: Orgad Shaneh <orgads@gmail.com>
Reviewed-by: André Hartmann <aha_1980@gmx.de>

src/plugins/diffeditor/diffview.cpp

@@ -38,7 +38,7 @@
 namespace DiffEditor {
 namespace Internal {
 
-IDiffView::IDiffView(QObject *parent) : QObject(parent), m_supportsSync(false)
+IDiffView::IDiffView(QObject *parent) : QObject(parent)
 { }
 
 QIcon IDiffView::icon() const