[simple-scan] help: Use proper markup for menuitems

[Andre Klapper <aklapper src gnome org>]

commit bc813379a6eba1f88f57d01625b94cb6955c0d21
Author: Andre Klapper <a9016009 gmx de>
Date:   Fri Feb 7 14:55:58 2020 +0100

    help: Use proper markup for menuitems

 help/C/crop.page | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
---
diff --git a/help/C/crop.page b/help/C/crop.page
index bab1da2..2ac8c6d 100644
--- a/help/C/crop.page
+++ b/help/C/crop.page
@@ -27,7 +27,8 @@
     
     <steps>
       <title>Use Right Click</title>
-      <item><p>Right click anywhere on the image area and select "Crop".</p></item>
+      <item><p>Right click anywhere on the page.</p></item>
+      <item><p>Select <gui style="menuitem">Crop</gui>.</p></item>
       <item><p>Choose one of the fixed crop frames, or select "Custom" to manually
        set the crop frame's dimensions by dragging its borders.</p></item>
       <item><p>Click and hold the frame to move it to the desired position.</p></item>