bin/dev.sh: Improve informational messages to user

Fix typos, correct grammar and clarify some instructions in user
messages.

bin/dev.sh

@@ -40,5 +40,5 @@ source $ALIASROOT
 echo -e "You can use the following aliases :\n"
 echo -e "\t memopol-code : Go into the repository and activate the virtualenv"
 echo -e "\t memopol-launch : Run the development server"
-echo -e "\t memopoll-update-all : Get all the production data"
+echo -e "\t memopol-update-all : Get all the production data"
 echo -e "\t memopol-refresh-scores : Refresh all scores"