Add info about buffer widening to the documentation.

doc/org.texi

@@ -940,6 +940,12 @@ been defined in the setup).  Reverse sorting is possible as well.  You can
 also supply your own function to extract the sorting key.  With a @kbd{C-u}
 prefix, sorting will be case-sensitive.  With two @kbd{C-u C-u} prefixes,
 duplicate entries will also be removed.
+@kindex C-x n s
+@item C-x n s
+Narrow buffer to current subtree.
+@kindex C-x n w
+@item C-x n w
+Widen buffer to remove a narrowing.
 @kindex C-c *
 @item C-c *
 Turn a normal line or plain list item into a headline (so that it

doc/orgcard.tex

@@ -311,10 +311,8 @@ are preserved on all copies.
 \key{insert new heading after subtree}{C-RET}
 \key{insert new TODO entry/checkbox item}{M-S-RET}
 
-\key{promote current heading up one level}{M-LEFT}
-\key{demote current heading down one level}{M-RIGHT}
-\key{promote current subtree up one level}{M-S-LEFT}
-\key{demote current subtree down one level}{M-S-RIGHT}
+\key{promote/demote heading}{M-LEFT/RIGHT}
+\metax{promote/demote current subtree}{M-S-LEFT/RIGHT}
 
 \key{move subtree/list item up/down}{M-S-UP/DOWN}
 \key{refile subtree}{C-c C-w}
@@ -322,6 +320,7 @@ are preserved on all copies.
 \key{copy subtree}{C-c C-x M-w}
 \key{yank subtree}{C-c C-x C-y}
 \key{narrow buffer to current subtree}{C-x n s}
+\key{widen restriction to full buffer}{C-x n w}
 
 \section{Archiving}