Allow using '(' and ')' in wxFileConfig entry names unescaped.

There is no real reason to escape the parentheses in the key entries, they're
not special.

Closes #13584.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@70184 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/common/fileconf.cpp

@@ -2111,7 +2111,7 @@ static wxString FilterOutEntryName(const wxString& str)
 #if !wxUSE_UNICODE
             ((unsigned char)c < 127) &&
 #endif // ANSI
-         !wxIsalnum(c) && !wxStrchr(wxT("@_/-!.*%"), c) )
+         !wxIsalnum(c) && !wxStrchr(wxT("@_/-!.*%()"), c) )
     {
       strResult += wxT('\\');
     }