doc: Fix typo in DM parameters
@@ -482,8 +482,14 @@ arguments used for configuration. Here is a table describing these emulated dev
If it is not set, the virtual display will use 1280x720 resolution in windowed mode.
* ``width`` specifies the width of the virtual display window in pixels.
* ``height`` specifies the height of the virtual display window in pixels.
- * ``x_off`` specifies the x offfset of the virtual display window from the upper-left corner of screen.
- * ``y_off`` specifies the y offfset of the virtual display window from the upper-left corner of screen.
+ * ``x_off`` specifies the x offset of the virtual display window from the
+ upper-left corner of the screen.
+ * ``y_off`` specifies the y offset of the virtual display window from the
+ upper-left corner of the screen.
+
+ For example: ``geometry=1280x720+100+50`` specifies a window 1280 pixels
+ wide by 720 high, with the top left corner 100 pixels right and 50 pixels
+ down from the top left corner of the screen.
* - ``passthru``
- Indicates a passthrough device. Use the parameter with the format
