message: Add F5 as Sync hotkey (in addition to Ctrl+R) (win)
diff: <KeyBinding Key="W" Modifiers="Control" Command="{x:Static toggl:KeyboardShortcuts.Hide}" />
  <KeyBinding Key="F4" Modifiers="Control" Command="{x:Static toggl:KeyboardShortcuts.Hide}" />
  <KeyBinding Key="R" Modifiers="Control" Command="{x:Static toggl:KeyboardShortcuts.Sync}" />
  + <KeyBinding Key="F5" Command="{x:Static toggl:KeyboardShortcuts.Sync}" />
  <KeyBinding Key="E" Modifiers="Control" Command="{x:Static toggl:KeyboardShortcuts.EditRunning}" />
  <KeyBinding Key="D" Modifiers="Control" Command="{x:Static toggl:KeyboardShortcuts.ToggleManualMode}" />
  <KeyBinding Key="V" Modifiers="Control" Command="{x:Static toggl:KeyboardShortcuts.NewFromPaste}" />
  "{Binding Path=IsEnabled, RelativeSource={RelativeSource Self}, Mode=OneWay, Converter={StaticResource BooleanToVisibility}}"
  />
  <Separator />
  - <MenuItem Header="Sync" InputGestureText="Ctrl+R"
  + <MenuItem Header="Sync" InputGestureText="F5"
  Command="{x:Static toggl:KeyboardShortcuts.Sync}"/>
  <MenuItem Header="Reports"
  Command="{x:Static toggl:KeyboardShortcuts.Reports}"/>
  