add hide/unhide for renderkey

Views/GlobalSettingsWindow.axaml

@@ -15,7 +15,18 @@
                     <TextBox Name="SheepItUsernameTextBox" Text="{Binding SheepItUsername}"/>
                     
                     <TextBlock Text="Render Key:" Margin="0,10,0,0"/>
-                    <TextBox Name="SheepItRenderKeyTextBox" Text="{Binding SheepItRenderKey}" PasswordChar="*"/>
+                    <Grid ColumnDefinitions="*,Auto">
+                        <TextBox Name="SheepItRenderKeyTextBox" 
+                                 Grid.Column="0" 
+                                 Text="{Binding SheepItRenderKey}" 
+                                 PasswordChar="*"
+                                 Margin="0,0,5,0"/>
+                        <Button Name="ToggleRenderKeyButton" 
+                                Grid.Column="1" 
+                                Content="👁" 
+                                Width="40"
+                                ToolTip.Tip="Show/Hide Render Key"/>
+                    </Grid>
                 </StackPanel>
             </TabItem>
         </TabControl>