Everywhere: Replace a bundle of dbg with dbgln.

These changes are arbitrarily divided into multiple commits to make it
easier to find potentially introduced bugs with git bisect.Everything:

The modifications in this commit were automatically made using the
following command:

    find . -name '*.cpp' -exec sed -i -E 's/dbg\(\) << ("[^"{]*");/dbgln\(\1\);/' {} \;

Services/WindowServer/Compositor.cpp

@@ -874,7 +874,7 @@ void Compositor::recompute_occlusions()
     });
 
 #ifdef OCCLUSIONS_DEBUG
-    dbg() << "OCCLUSIONS:";
+    dbgln("OCCLUSIONS:");
 #endif
 
     auto screen_rect = Screen::the().rect();