Use existing arg_dry_run function.

And drop the `-n` short flag until we decide to commit to using it
generally.

Author: ehuss

src/bin/cargo/commands/clean.rs

@@ -14,13 +14,7 @@ pub fn cli() -> Command {
         .arg_target_triple("Target triple to clean output for")
         .arg_target_dir()
         .arg_manifest_path()
-        .arg(
-            flag(
-                "dry-run",
-                "Display what would be deleted without deleting anything",
-            )
-            .short('n'),
-        )
+        .arg_dry_run("Display what would be deleted without deleting anything")
         .after_help("Run `cargo help clean` for more detailed information.\n")
 }
 
@@ -38,7 +32,7 @@ pub fn exec(config: &mut Config, args: &ArgMatches) -> CliResult {
         requested_profile: args.get_profile_name(config, "dev", ProfileChecking::Custom)?,
         profile_specified: args.contains_id("profile") || args.flag("release"),
         doc: args.flag("doc"),
-        dry_run: args.flag("dry-run"),
+        dry_run: args.dry_run(),
     };
     ops::clean(&ws, &opts)?;
     Ok(())

tests/testsuite/cargo_clean/help/stdout.log

@@ -5,7 +5,7 @@ Usage: cargo[EXE] clean [OPTIONS]
 Options:
       --doc                 Whether or not to clean just the documentation directory
   -q, --quiet               Do not print cargo log messages
-  -n, --dry-run             Display what would be deleted without deleting anything
+      --dry-run             Display what would be deleted without deleting anything
   -v, --verbose...          Use verbose output (-vv very verbose/build.rs output)
       --color <WHEN>        Coloring: auto, always, never
       --config <KEY=VALUE>  Override a configuration value