Fix binary usage comments

src/bin/nbtdump.rs

@@ -8,7 +8,7 @@ use std::path::PathBuf;
 use anyhow::Result;
 use clap::Parser;
 
-/// Command line arguments for nbtdump
+/// Dump a Minecraft NBT data file in a human-readable format
 #[derive(Debug, Parser)]
 struct Args {
 	/// Filename to dump

src/bin/regiondump.rs

@@ -8,7 +8,7 @@ use std::path::PathBuf;
 use anyhow::Result;
 use clap::Parser;
 
-/// Command line arguments for regiondump
+/// Dump a Minecraft NBT region file in a human-readable format
 #[derive(Debug, Parser)]
 struct Args {
 	/// Filename to dump

src/core/mod.rs

@@ -18,7 +18,7 @@ use region_processor::RegionProcessor;
 use tile_mipmapper::TileMipmapper;
 use tile_renderer::TileRenderer;
 
-/// Command line arguments for minedmap
+/// Generate map tiles from Minecraft save data
 #[derive(Debug, Parser)]
 pub struct Args {
 	/// Number of parallel threads to use for processing