Support float, double and file name values in wxGenericValidator.

Currently these values can only be read from/written to wxTextCtrl but support
for other controls (e.g. wxSpinCtrlDouble for float/double) could be added in
the future.

Closes #13304.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@68217 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

docs/changes.txt

@@ -437,6 +437,10 @@ Major new features in this release
 2.9.3:
 ------
 
+All (GUI):
+
+- Support float, double and file name values in wxGenericValidator (troelsk).
+
 GTK:
 
 - Generate events for two auxiliary mouse buttons in wxGTK (Marcin Wojdyr).