Qt5 return expected QVariants int sizes

Grep'ing the Qt source code, most of the places call toInt()
on the QVariants returned from Qt::ImCursorPosition and
Qt::ImAnchorPosition (toUInt() is probably a bug). So actually
deliver these (and fix the 32bit build with the sal_Int32
ambiguity - there is no "signed long" QVariant constructor).

Change-Id: Id6b8fbabb8156692592bdef48437db140c6b7cca
Reviewed-on: https://gerrit.libreoffice.org/73349
Tested-by: Jenkins
Tested-by: Rene Engelhard <rene@debian.org>
Reviewed-by: Jan-Marek Glogowski <glogow@fbihome.de>

vcl/qt5/Qt5Widget.cxx

@@ -629,7 +629,7 @@ QVariant Qt5Widget::inputMethodQuery(Qt::InputMethodQuery property) const
         {
             sal_Int32 nCursorPos, nAnchor;
             if (lcl_retrieveSurrounding(nCursorPos, nAnchor, nullptr, nullptr))
-                return QVariant(nCursorPos);
+                return QVariant(static_cast<int>(nCursorPos));
             [[fallthrough]];
         }
         case Qt::ImCursorRectangle:
@@ -643,7 +643,7 @@ QVariant Qt5Widget::inputMethodQuery(Qt::InputMethodQuery property) const
         {
             sal_Int32 nCursorPos, nAnchor;
             if (lcl_retrieveSurrounding(nCursorPos, nAnchor, nullptr, nullptr))
-                return QVariant(nAnchor);
+                return QVariant(static_cast<int>(nAnchor));
             [[fallthrough]];
         }
         case Qt::ImCurrentSelection: