Parse argument of `pijul log --output-format` strictly

Dependencies

• [2] U6TQX5Z2 pager function respects cli option and user config files, PAGER env var
• [3] RUBBHYZ7 Removing unnecessary async/await
• [4] OU6JOR3C Add path filtering for log, add json output for log
• [5] SXEYMYF7 Fixing the bad changes in history (unfortunately, by rebooting).

Change contents

• replacement in pijul/src/commands/log.rs at line 44
  [3.1718]→[3.347:418](∅→∅)
  − #[clap(long = "output-format")]

  − output_format: Option<String>,
  [3.1718]

  [3.418]
  + #[clap(long = "output-format", value_enum)]

  + output_format: Option<OutputFormat>,
• edit in pijul/src/commands/log.rs at line 444
  [3.14039]

  [3.14039]
  + }

  +

  + /// The output format to use when printing logs.

  + #[derive(Default, Copy, Clone, Debug, clap::ValueEnum)]

  + enum OutputFormat {

  + #[default]

  + Plaintext,

  + Json,
• replacement in pijul/src/commands/log.rs at line 464
  [2.2307]→[2.2307:2379](∅→∅),[2.2379]→[3.14372:14431](∅→∅),[3.14372]→[3.14372:14431](∅→∅)
  − match log_iter.cmd.output_format.as_ref().map(|s| s.as_str()) {

  − Some(s) if s.eq_ignore_ascii_case("json") => {
  [2.2307]

  [2.2380]
  + match log_iter.cmd.output_format.unwrap_or_default() {

  + OutputFormat::Json => {
• replacement in pijul/src/commands/log.rs at line 468
  [3.14535]→[2.2451:2535](∅→∅)
  − _ => log_iter.for_each(|entry| match write!(&mut stdout, "{}", entry) {
  [3.14535]

  [2.2535]
  + OutputFormat::Plaintext => log_iter.for_each(|entry| match write!(&mut stdout, "{}", entry) {