Add parameters documentation button

* Add button next to the custom parameters text box that will open the user's preferred browser to the online steam documentation.

Author: rex706

SAM/SettingsWindow.xaml

@@ -134,7 +134,8 @@
                     <CheckBox x:Name="TcpCheckBox" Content="-tcp" HorizontalAlignment="Left" Margin="203,98,0,0" VerticalAlignment="Top" ToolTip="Forces connection to Steam backend to be via TCP."/>
                     <CheckBox x:Name="TenFootCheckBox" Content="-tenfoot" HorizontalAlignment="Left" Margin="203,121,0,0" VerticalAlignment="Top" ToolTip="Start Steam in Big Picture Mode."/>
                     <CheckBox x:Name="CustomParametersCheckBox" Content="" HorizontalAlignment="Left" Margin="12,150,0,0" VerticalAlignment="Top" Foreground="#FFD1D1D1" Checked="CustomParametersCheckBox_Checked" Unchecked="CustomParametersCheckBox_Unchecked" ToolTip="Toggle custom parameters"/>
-                    <TextBox x:Name="CustomParametersTextBox" HorizontalAlignment="Left" Height="19" Margin="34,146,0,0" TextWrapping="Wrap" VerticalAlignment="Top" Width="294" IsEnabled="False"/>
+                    <TextBox x:Name="CustomParametersTextBox" HorizontalAlignment="Center" Height="19" Margin="33,146,35,0" TextWrapping="Wrap" VerticalAlignment="Top" Width="266" IsEnabled="False"/>
+                    <Button x:Name="CustomParamsHelpButton" Content="?" Margin="0,146,8,13" Height="23" Width="25" HorizontalAlignment="Right" ToolTip="Online documentation" Click="CustomParamsHelpButton_Click"/>
                 </Grid>
             </TabItem>
         </TabControl>

SAM/SettingsWindow.xaml.cs

@@ -468,5 +468,10 @@ private void AutoReloadCheckBox_Unchecked(object sender, RoutedEventArgs e)
         {
             AutoReloadIntervalSpinBox.IsEnabled = false;
         }
+
+        private void CustomParamsHelpButton_Click(object sender, RoutedEventArgs e)
+        {
+            Process.Start("https://developer.valvesoftware.com/wiki/Command_Line_Options#Steam_.28Windows.29");
+        }
     }
 }