Substitute usage information into the documentation

This will simplify keeping documentation in sync with the code.

cli/src/settings/report.rs

@@ -2,6 +2,7 @@
 
 use crate::argparse::{Condition, Filter};
 use crate::settings::util::table_with_keys;
+use crate::usage::{self, Usage};
 use anyhow::{anyhow, bail, Result};
 use std::convert::{TryFrom, TryInto};
 
@@ -30,6 +31,7 @@ pub(crate) struct Column {
 /// Task property to display in a report
 #[derive(Clone, Debug, PartialEq)]
 pub(crate) enum Property {
+    // NOTE: when adding a property here, add it to get_usage, below, as well.
     /// The task's ID, either working-set index or Uuid if not in the working set
     Id,
 
@@ -59,6 +61,7 @@ pub(crate) struct Sort {
 /// Task property to sort by
 #[derive(Clone, Debug, PartialEq)]
 pub(crate) enum SortBy {
+    // NOTE: when adding a property here, add it to get_usage, below, as well.
     /// The task's ID, either working-set index or a UUID prefix; working
     /// set tasks sort before others.
     Id,
@@ -212,6 +215,34 @@ impl TryFrom<&toml::Value> for SortBy {
     }
 }
 
+pub(crate) fn get_usage(u: &mut Usage) {
+    u.report_properties.push(usage::ReportProperty {
+        name: "id",
+        as_sort_by: Some("Sort by the task's shorthand ID"),
+        as_column: Some("The task's shorthand ID"),
+    });
+    u.report_properties.push(usage::ReportProperty {
+        name: "uuid",
+        as_sort_by: Some("Sort by the task's full UUID"),
+        as_column: Some("The task's full UUID"),
+    });
+    u.report_properties.push(usage::ReportProperty {
+        name: "active",
+        as_sort_by: None,
+        as_column: Some("`*` if the task is active (started)"),
+    });
+    u.report_properties.push(usage::ReportProperty {
+        name: "description",
+        as_sort_by: Some("Sort by the task's description"),
+        as_column: Some("The task's description"),
+    });
+    u.report_properties.push(usage::ReportProperty {
+        name: "tags",
+        as_sort_by: None,
+        as_column: Some("The task's tags"),
+    });
+}
+
 #[cfg(test)]
 mod test {
     use super::*;