Organize help page into mode specific sections

Author: Brandon-Shippy

rust/crates/sift_cli/src/cli/mod.rs

@@ -451,17 +451,21 @@ pub struct ImportHdf5Args {
 
     /// (two-d / compound) Index of the time column or field. Defaults to 0.
     /// Mutually exclusive with --time-field and --time-name.
-    #[arg(long, conflicts_with_all = ["time_field", "time_name"])]
+    #[arg(
+        long,
+        conflicts_with_all = ["time_field", "time_name"],
+        help_heading = "Two-d schema options",
+    )]
     pub time_index: Option<u64>,
 
     /// (compound) Name of the time field. Mutually exclusive with --time-index
     /// and --time-name.
-    #[arg(long, conflicts_with = "time_name")]
+    #[arg(long, conflicts_with = "time_name", help_heading = "Compound schema options")]
     pub time_field: Option<String>,
 
     /// (one-d) Leaf name of the time dataset when it doesn't match the default
     /// auto-detected names (time, timestamp, timestamps, ts). Mutually exclusive
     /// with --time-index and --time-field.
-    #[arg(long)]
+    #[arg(long, help_heading = "One-d schema options")]
     pub time_name: Option<String>,
 }