Fixing a bug with the salt argument in `mv`

Dependencies

• [2] 2RXOCWUW Making libpijul deterministic (and getting rid of `rand`)
• [3] L4JXJHWX pijul/*: reorganize imports and remove extern crate
• [4] AEPEFS7O Write help for each argument
• [5] 4OCC6D42 Recursive add
• [6] SXEYMYF7 Fixing the bad changes in history (unfortunately, by rebooting).
• [7] ZHABNS3S Canonicalize all paths
• [8] EEOOHGQQ More atomic "file moves+transaction"
• [9] I24UEJQL Various post-fire fixes
• [10] TZVUNELW Documentation comments
• [11] TPQHDDNC pijul add --force know adds ignored files
• [12] I52XSRUH Massive cleanup, and simplification

Change contents

• replacement in pijul/src/commands/file_operations.rs at line 6
  [3.647]→[3.2405:2421](∅→∅),[3.2405]→[3.2405:2421](∅→∅)
  − use clap::Clap;
  [3.647]

  [3.4127]
  + use clap::{Clap, ArgSettings};
• edit in pijul/src/commands/file_operations.rs at line 17
  [3.169313]

  [3.3664]
  +

  + #[clap(setting = ArgSettings::Hidden, long = "salt")]

  + salt: Option<u64>,
• edit in pijul/src/commands/file_operations.rs at line 25
  [3.169338]→[2.1174:1198](∅→∅)
  −

  − salt: Option<u64>,
• replacement in pijul/src/commands/file_operations.rs at line 123
  [3.58]→[2.1274:1301](∅→∅)
  − #[clap(long = "salt")]
  [3.58]

  [2.1301]
  + #[clap(setting = ArgSettings::Hidden, long = "salt")]