menu: allow names in card content and simplify define single card decks

Signed-off-by: Janar Sööt <janar.soot@gmail.com>

config/example-menu.cfg

@@ -171,6 +171,11 @@
 #items:
 #   It accepts only 'card' elements. You are able to switch between different card screens
 #   by using encoder or up/down buttons.
+#content:
+#   It allows quickly define single card decks by adding content directly to deck.
+#   You have to remove deck item attribute and use named items in content.
+#   The menu functionality will then internally create one card item for this deck.
+#   This is optional.
 
 #[menu card1]
 #type: card
@@ -179,6 +184,10 @@
 #   Card screen content. Each line represents display line.
 #   Quotes can be used in the beginning and end of line.
 #   Rendered elements are available for output formatting as {0}..{x}. It's always string type.
+#   It's possible directly use menu item names in content by leaving items attribute out or empty
+#   and use menu items names directly in content as {msg,xpos|ypos}. The menu functionality will then
+#   internally build a item list and replace names with indexes in content.
+#   This is optional.
 #items:
 #   List of elements in card. Each line represents a single index for content formatting.
 #   It's possible to show multiple elements in one place by separating them with comma on single line.