Add habit key K to refcard.

doc/orgcard.tex

@@ -634,7 +634,7 @@ after  ``{\tt :}'', and dictionary words elsewhere.
 \key{delete other windows}{o}
 \key{view mode dipatcher}{v}
 \key{switch to day/week/month/year view}{d w vm vy}
-\key{toggle diary entries / time grid}{D / G}
+\key{toggle diary entries / time grid / habits}{D / G / K}
 \key{toggle entry text / clock report}{E / R}
 \key{toggle display of logbook entries}{l / v l/L}
 \key{toggle inclusion of archived trees/files}{v a/A}