Merge branch 'search-desctext'

wxSearchCtrl fixes for wxMSW and add "hint" property to its XRC handler.

See https://github.com/wxWidgets/wxWidgets/pull/691

docs/changes.txt

@@ -176,6 +176,7 @@ All (GUI):
 - Add wxFontPickerCtrl::SetMinPointSize() (Andreas Falkenhahn).
 - Add Set/GetFooter/Text/Icon() to wxRichMessageDialog (Tobias Taschner)
 - Add wxFloatingPointValidator::SetFactor().
+- Add "hint" property to wxSearchCtrl XRC handler.
 
 wxGTK:
 

docs/doxygen/overviews/xrc_format.h

@@ -1950,6 +1950,9 @@ child and the second one for right/bottom child window.
 @hdr3col{property, type, description}
 @row3col{value, @ref overview_xrcformat_type_text,
     Initial value of the control (default: empty).}
+@row3col{hint, @ref overview_xrcformat_type_text,
+    Descriptive text shown in the empty control (default: "Search"). This
+    property is new since wxWidgets 3.1.1.}
 @endTable