convert SW_KeyState to scoped enum

and drop unused InsDel_* enumerators.
Also rename to SwKeyState to make it a little shorter and more
consistent with other naming.

Change-Id: I837ea8d64a0f26426567dcf78750939fc959a4a4

compilerplugins/clang/unusedenumconstants.py

@@ -136,6 +136,7 @@ for d in definitionSet:
          "include/svl/zforlist.hxx",
          "include/svtools/svtabbx.hxx",
          "include/vcl/print.hxx", # NupOrderType, from UI combobox
+         "sw/source/uibase/inc/swcont.hxx", # RegionMode, from UI; ContentTypeId, from UI(registry)
         # represents constants from an external API
          "opencl/inc/opencl_device_selection.h",
          "vcl/inc/sft.hxx",