Remove qsettings docs as ConfigHandler documents the same

docs/dev/qsettings.md

@@ -1,40 +0,0 @@
-- List of Buttons
-    - value: "buttons"
-    - type: <QList<int> >
-    - description: list of buttons to be shown with the selection.
-- Last saved image path
-    - value: "savePath"
-    - type: QString
-    - description: initial path of the save scheenshot widget.
-- Drawing color
-    - value: "drawColor"
-    - type: QColor
-    - description: color of the drawing tools.
-- UI color
-    - value: "uiColor"
-    - type: QColor
-    - description: color of buttons and the selection.
-- contast UI color
-    - value: "contastUiColor"
-    - type: QColor
-    - description: color of buttons awhile selected.
-- show Help message
-    - value: "showHelp"
-    - type: bool
-    - description: show Help messages in capture mode.
-- show desktop notifications
-    - value: "showDesktopNotification"
-    - type: bool
-    - description: show every desktop notification.
-- filename pattern
-    - value: "filenamePattern"
-    - type: QString
-    - description: pattern for the saved files.
-- show System Tray
-    - value: "showTrayIcon"
-    - type: bool
-    - description: show Tray Icon in the taskbar.
-- Keep Open App Launcher
-    - value: "keepOpenAppLauncher"
-    - type: bool
-    - description: don't close the app launcher's window after selecting an app.