Beautifier: Simplify GeneralSettings implementation

Change-Id: Ib8b8f0b1cab3d9bbacf24009c0bd546660c19906
Reviewed-by: Alessandro Portale <alessandro.portale@qt.io>
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>

src/plugins/beautifier/generalsettings.cpp

@@ -14,17 +14,8 @@ using namespace Utils;
 
 namespace Beautifier::Internal {
 
-static GeneralSettings *m_instance;
-
-GeneralSettings *GeneralSettings::instance()
-{
-    return m_instance;
-}
-
 GeneralSettings::GeneralSettings()
 {
-    m_instance = this;
-
     setId(Constants::OPTION_GENERAL_ID);
     setDisplayName(Tr::tr("General"));
     setCategory(Constants::OPTION_CATEGORY);

src/plugins/beautifier/generalsettings.h

@@ -14,8 +14,6 @@ class GeneralSettings : public Core::PagedSettings
 public:
     GeneralSettings();
 
-    static GeneralSettings *instance();
-
     QList<Utils::MimeType> allowedMimeTypes() const;
 
     Utils::BoolAspect autoFormatOnSave;