Make the exit() methods in QEventLoop and QThread be slots

The documentation for QCoreApplication::exit() even refers to it as
such. Instead of refactoring the documentation to explain that it isn't,
just make it a slot and do the same for the other classes.

Complements 2e6c37fe51.

[ChangeLog][QtCore][QEventLoop] exit() is now a slot, like quit().

[ChangeLog][QtCore][QThread] exit() is now a slot, like quit().

Change-Id: Ic42004c9bf71440eb433fffd167f4a1b89bcac80
Reviewed-by: David Faure <david.faure@kdab.com>

src/corelib/kernel/qeventloop.h

@@ -70,7 +70,6 @@ public:
     void processEvents(ProcessEventsFlags flags, int maximumTime);
 
     int exec(ProcessEventsFlags flags = AllEvents);
-    void exit(int returnCode = 0);
     bool isRunning() const;
 
     void wakeUp();
@@ -78,6 +77,7 @@ public:
     bool event(QEvent *event) override;
 
 public Q_SLOTS:
+    void exit(int returnCode = 0);
     void quit();
 };
 

src/corelib/thread/qthread.h

@@ -99,8 +99,6 @@ public:
     void setStackSize(uint stackSize);
     uint stackSize() const;
 
-    void exit(int retcode = 0);
-
     QAbstractEventDispatcher *eventDispatcher() const;
     void setEventDispatcher(QAbstractEventDispatcher *eventDispatcher);
 
@@ -115,6 +113,7 @@ public:
 public Q_SLOTS:
     void start(Priority = InheritPriority);
     void terminate();
+    void exit(int retcode = 0);
     void quit();
 
 public: