LanguageClient: remove unneeded forward delaration

Change-Id: I02e8dd07f8f04c82cdf31fc536c7d23924539296
Reviewed-by: Christian Stenger <christian.stenger@qt.io>
Reviewed-by: David Schulz <david.schulz@qt.io>

src/plugins/languageclient/languageclientsettings.cpp

@@ -425,6 +425,12 @@ void BaseSettings::fromMap(const QVariantMap &map)
     m_languageFilter.filePattern = map[filePatternKey].toStringList();
 }
 
+static LanguageClientSettingsPage &settingsPage()
+{
+    static LanguageClientSettingsPage settingsPage;
+    return settingsPage;
+}
+
 void LanguageClientSettings::init()
 {
     settingsPage().init();
@@ -459,12 +465,6 @@ void LanguageClientSettings::toSettings(QSettings *settings,
     settings->endGroup();
 }
 
-LanguageClientSettingsPage &LanguageClientSettings::settingsPage()
-{
-    static LanguageClientSettingsPage settingsPage;
-    return settingsPage;
-}
-
 void StdIOSettings::applyFromSettingsWidget(QWidget *widget)
 {
     if (auto settingsWidget = qobject_cast<StdIOSettingsWidget *>(widget)) {

src/plugins/languageclient/languageclientsettings.h

@@ -117,8 +117,6 @@ protected:
     StdIOSettings &operator=(StdIOSettings &&other) = default;
 };
 
-class LanguageClientSettingsPage;
-
 class LanguageClientSettings
 {
 public:
@@ -126,9 +124,6 @@ public:
     static QList<BaseSettings *> fromSettings(QSettings *settings);
     static QList<BaseSettings *> currentPageSettings();
     static void toSettings(QSettings *settings, const QList<BaseSettings *> &languageClientSettings);
-
-private:
-    static LanguageClientSettingsPage &settingsPage();
 };
 
 class BaseSettingsWidget : public QWidget