bin/tau: update cli help message

bin/tau/tau-cli/src/main.rs

@@ -75,22 +75,25 @@ enum TauSubcommand {
     ///   New task with description:
     ///     tau add Add more info to tau desc:"some awesome description"
     ///   New task with project and assignee:
-    ///     tau add Third task project:p2p assign:rusty
+    ///     tau add Third task project:p2p Arusty
     ///   Add a task with due date September 12th and rank of 4.6:
     ///     tau add Task no. Four due:1209 rank:4.6
     ///
     /// Notice that if the command does not have "desc" key it will open
     /// an Editor so you can write the description there.
     ///
-    /// Also note that "project" and "assign" keys can have multiple
+    /// Also note that "project" key can have multiple
     /// comma-separated values.
+    /// "assign" on the other hand uses '@' character but also could be
+    /// multiple values, but like so:
+    /// @person1 @person2
     ///
     /// All keys example:
-    ///     tau add Improve CLI desc:"Description here" project:tau,ircd assign:dave,rusty due:0210 rank:2.2
+    ///     tau add Improve CLI desc:"Description here" project:tau,ircd @dave @rusty due:0210 rank:2.2
     ///
     #[clap(verbatim_doc_comment)]
     Add {
-        /// Pairs of key:value (e.g. desc:description assign:dark).
+        /// Pairs of key:value (e.g. desc:description @dark).
         values: Vec<String>,
     },