Add menubar config (#70)

Author: esimkowitz

docs/config.mdx

@@ -44,6 +44,7 @@ use ":" as level separators.
 | window:bgcolor | string | set the window background color (should be hex: #xxxxxx) |
 | window:reducedmotion | bool | set to true to disable most animations |
 | window:tilegapsize | int | set to change override default gap between blocks |
+| window:showmenubar | bool | set to use the OS-native menu bar (Windows and Linux only, requires app restart) |
 | window:nativetitlebar | bool | set to use the OS-native title bar, rather than the overlay (Windows and Linux only, requires app restart) |
 | window:disablehardwareacceleration | bool | set to disable Chromium hardware acceleration to resolve graphical bugs (requires app restart) |
 | telemetry:enabled | bool | set to enable/disable telemetry |