feat: set + validate intentional MSRV (1.72.0)

[reubeno]

Picking 1.72.0 for now; this required removing usage of a few convenience functions that haven't been around too long, fixing a few minor compilation errors, and downgrading clap. When we're ready to move the MSRV higher, we can revert these changes.

[github-actions]

Test Results

399 tests   384 ✅  1m 22s ⏱️
 64 suites   15 💤
  8 files      0 ❌

Results for commit a8ba798.

♻️ This comment has been updated with latest results.

[github-actions]

Performance Benchmark Report

Benchmark name	Baseline (ns)	Test/PR (ns)	Delta (ns)	Delta %
expand_one_string	3455 ns	3458 ns	+3 ns	🟠 +0.09%
instantiate_shell	60885 ns	61417 ns	+532 ns	🟠 +0.87%
instantiate_shell_with_init_scripts	27774067 ns	27617168 ns	-156899 ns	🟢 -0.56%
parse_bash_completion	5518275 ns	5531092 ns	+12817 ns	🟠 +0.23%
parse_sample_script	8824 ns	8804 ns	-20 ns	🟢 -0.23%
run_echo_builtin_command	94492 ns	94577 ns	+85 ns	🟠 +0.09%
run_one_builtin_command	112047 ns	112193 ns	+146 ns	🟠 +0.13%
run_one_external_command	1934672 ns	1944573 ns	+9901 ns	🟠 +0.51%
run_one_external_command_directly	1002603 ns	1003621 ns	+1018 ns	🟠 +0.10%

Code Coverage Report

Package	Base Coverage	New Coverage	Difference
/home/runner/work/brush/brush/brush-core/src/arithmetic.rs	🟢 99.01%	🟢 99.01%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/builtin.rs	🔴 31.21%	🔴 31.21%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/builtins/alias.rs	🟢 83.87%	🟢 83.87%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/builtins/bg.rs	🔴 0%	🔴 0%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/builtins/break_.rs	🟢 90%	🟢 90%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/builtins/builtin_.rs	🟢 100%	🟢 100%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/builtins/cd.rs	🟢 88.57%	🟢 88.57%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/builtins/colon.rs	🟢 100%	🟢 100%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/builtins/command.rs	🟢 93.26%	🟢 93.26%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/builtins/complete.rs	🔴 21.48%	🔴 21.48%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/builtins/continue_.rs	🟢 90%	🟢 90%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/builtins/declare.rs	🟢 82.83%	🟢 82.83%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/builtins/dirs.rs	🟢 90.48%	🟢 90.48%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/builtins/dot.rs	🟢 95.65%	🟢 95.65%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/builtins/echo.rs	🟢 86.84%	🟢 86.84%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/builtins/enable.rs	🟢 91.07%	🟢 91.07%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/builtins/eval.rs	🟢 100%	🟢 100%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/builtins/exec.rs	🟢 90.32%	🟢 90.32%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/builtins/exit.rs	🟢 100%	🟢 100%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/builtins/export.rs	🟢 88.73%	🟢 88.73%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/builtins/false_.rs	🟢 100%	🟢 100%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/builtins/fg.rs	🔴 0%	🔴 0%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/builtins/getopts.rs	🟢 97.7%	🟢 97.7%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/builtins/help.rs	🟢 91.86%	🟢 91.86%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/builtins/jobs.rs	🔴 41.86%	🔴 41.86%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/builtins/kill.rs	🔴 0%	🔴 0%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/builtins/let_.rs	🟢 100%	🟢 100%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/builtins/mod.rs	🟢 94.61%	🟢 94.61%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/builtins/popd.rs	🟢 94.12%	🟢 94.12%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/builtins/printf.rs	🟢 91.18%	🟢 91.18%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/builtins/pushd.rs	🟢 91.3%	🟢 91.3%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/builtins/pwd.rs	🟢 89.47%	🟢 89.47%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/builtins/read.rs	🟠 73.53%	🟠 73.53%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/builtins/return_.rs	🟢 83.33%	🟢 83.33%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/builtins/set.rs	🟢 76.64%	🟢 76.64%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/builtins/shift.rs	🟢 100%	🟢 100%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/builtins/shopt.rs	🟢 88.39%	🟢 88.39%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/builtins/test.rs	🟢 100%	🟢 100%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/builtins/trap.rs	🟢 83.15%	🟢 83.15%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/builtins/true_.rs	🟢 100%	🟢 100%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/builtins/type_.rs	🟢 90.27%	🟢 90.27%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/builtins/umask.rs	🔴 0%	🔴 0%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/builtins/unalias.rs	🔴 0%	🔴 0%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/builtins/unimp.rs	🔴 0%	🔴 0%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/builtins/unset.rs	🟢 94.64%	🟢 94.64%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/builtins/wait.rs	🟢 85.71%	🟢 85.71%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/commands.rs	🟢 92.86%	🟢 92.86%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/completion.rs	🔴 42.49%	🔴 42.49%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/env.rs	🟢 87.85%	🟢 87.85%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/error.rs	🔴 25%	🔴 25%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/escape.rs	🔴 14.91%	🔴 14.91%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/expansion.rs	🟢 95.95%	🟢 95.95%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/extendedtests.rs	🟠 64.15%	🟠 64.15%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/files.rs	🟠 66.67%	🟠 66.67%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/functions.rs	🟢 100%	🟢 100%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/interp.rs	🟢 93.11%	🟢 93.11%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/jobs.rs	🔴 41.45%	🔴 39.38%	🔴 -2.07%
/home/runner/work/brush/brush/brush-core/src/keywords.rs	🟢 96.88%	🟢 96.88%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/namedoptions.rs	🟠 52.34%	🟠 52.34%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/openfiles.rs	🔴 47.83%	🔴 46.15%	🔴 -1.68%
/home/runner/work/brush/brush/brush-core/src/options.rs	🟢 100%	🟢 100%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/patterns.rs	🟢 96.93%	🟢 96.93%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/prompt.rs	🟢 78.48%	🟢 78.48%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/regex.rs	🟢 100%	🟢 100%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/shell.rs	🟢 78.44%	🟢 78.12%	🔴 -0.32%
/home/runner/work/brush/brush/brush-core/src/tests.rs	🟠 50%	🟠 50%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/traps.rs	🟠 50%	🟠 50%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/users.rs	🔴 16.13%	🔴 16.13%	⚪ 0%
/home/runner/work/brush/brush/brush-core/src/variables.rs	🟢 79.91%	🟢 79.91%	⚪ 0%
/home/runner/work/brush/brush/brush-interactive/src/interactive_shell.rs	🟢 77.78%	🟢 77.78%	⚪ 0%
/home/runner/work/brush/brush/brush-parser/src/arithmetic.rs	🟢 100%	🟢 100%	⚪ 0%
/home/runner/work/brush/brush/brush-parser/src/ast.rs	🔴 29.36%	🔴 29.36%	⚪ 0%
/home/runner/work/brush/brush/brush-parser/src/error.rs	🟢 83.33%	🟢 83.33%	⚪ 0%
/home/runner/work/brush/brush/brush-parser/src/parser.rs	🟢 99.33%	🟢 99.33%	⚪ 0%
/home/runner/work/brush/brush/brush-parser/src/pattern.rs	🟢 100%	🟢 100%	⚪ 0%
/home/runner/work/brush/brush/brush-parser/src/prompt.rs	🟢 100%	🟢 100%	⚪ 0%
/home/runner/work/brush/brush/brush-parser/src/test_command.rs	🟢 100%	🟢 100%	⚪ 0%
/home/runner/work/brush/brush/brush-parser/src/tokenizer.rs	🟢 96.42%	🟢 96.42%	⚪ 0%
/home/runner/work/brush/brush/brush-parser/src/word.rs	🟢 100%	🟢 100%	⚪ 0%
/home/runner/work/brush/brush/brush-shell/src/main.rs	🟠 71.63%	🟠 70.92%	🔴 -0.71%
Overall Coverage	🟢 78.57%	🟢 78.48%	🔴 -0.09%

Minimum allowed coverage is 0%, this run produced 78.48%