update usage function - notes - a console notes manager using git
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       ---
 (DIR) commit 4b542b9c129690d0c0354f61b41bd2ee0edaf9a8
 (DIR) parent b3e4fc2cc7cae09643d83da834b3ee37b1274503
 (HTM) Author: Solene Rapenne <solene@perso.pw>
       Date:   Fri, 13 Jul 2018 20:10:28 +0200
       
       update usage function
       
       Diffstat:
         M notes                               |       3 +++
       
       1 file changed, 3 insertions(+), 0 deletions(-)
       ---
 (DIR) diff --git a/notes b/notes
       @@ -33,6 +33,9 @@ usage() {
                echo ""
                echo "  $NAME rm path"
                echo "     - delete file"
       +        echo ""
       +        echo "  $NAME last"
       +        echo "     - show files ordered by edition time"
        }
        
        # display a file tree of notes taken