Case in command support

[lu-zero]

Fixes #1052

[github-actions]

Performance Benchmark Report

Benchmark name	Baseline (μs)	Test/PR (μs)	Delta (μs)	Delta %
clone_shell_object	17.41 μs	17.02 μs	-0.39 μs	🟢 -2.22%
eval_arithmetic	0.15 μs	0.15 μs	0.00 μs	⚪ Unchanged
expand_one_string	1.56 μs	1.56 μs	0.00 μs	⚪ Unchanged
for_loop	25.65 μs	25.57 μs	-0.07 μs	⚪ Unchanged
full_peg_complex	58.67 μs	57.73 μs	-0.94 μs	⚪ Unchanged
full_peg_for_loop	6.32 μs	6.29 μs	-0.03 μs	⚪ Unchanged
full_peg_nested_expansions	16.75 μs	16.38 μs	-0.38 μs	🟢 -2.24%
full_peg_pipeline	4.38 μs	4.31 μs	-0.07 μs	⚪ Unchanged
full_peg_simple	1.83 μs	1.85 μs	0.01 μs	⚪ Unchanged
function_call	2.75 μs	2.77 μs	0.01 μs	⚪ Unchanged
instantiate_shell	55.88 μs	54.59 μs	-1.30 μs	🟢 -2.32%
instantiate_shell_with_init_scripts	26514.60 μs	25304.36 μs	-1210.24 μs	🟢 -4.56%
parse_peg_bash_completion	2104.90 μs	2080.52 μs	-24.39 μs	🟢 -1.16%
parse_peg_complex	20.34 μs	20.09 μs	-0.26 μs	🟢 -1.25%
parse_peg_for_loop	2.03 μs	2.02 μs	-0.01 μs	⚪ Unchanged
parse_peg_pipeline	2.26 μs	2.21 μs	-0.05 μs	⚪ Unchanged
parse_peg_simple	1.13 μs	1.12 μs	-0.01 μs	⚪ Unchanged
run_echo_builtin_command	17.93 μs	17.88 μs	-0.04 μs	⚪ Unchanged
tokenize_sample_script	3.37 μs	3.38 μs	0.00 μs	⚪ Unchanged

Code Coverage Report: Only Changed Files listed

Package	Base Coverage	New Coverage	Difference
brush-builtins/src/complete.rs	🟢 83.38%	🟢 75.06%	🔴 -8.32%
brush-builtins/src/declare.rs	🟢 86.6%	🟢 86.33%	🔴 -0.27%
brush-builtins/src/unset.rs	🟢 90.2%	🟢 88.24%	🔴 -1.96%
brush-core/src/commands.rs	🟢 91.7%	🟢 91.48%	🔴 -0.22%
brush-core/src/completion.rs	🟠 73.25%	🟠 72.02%	🔴 -1.23%
brush-core/src/expansion.rs	🟢 95.43%	🟢 95.36%	🔴 -0.07%
brush-core/src/extendedtests.rs	🟠 74.75%	🟠 73.23%	🔴 -1.52%
brush-core/src/extensions.rs	🔴 0%	🟢 100%	🟢 100%
brush-core/src/results.rs	🟢 83.33%	🟢 80.16%	🔴 -3.17%
brush-core/src/variables.rs	🟢 89%	🟢 88.83%	🔴 -0.17%
brush-parser/src/tokenizer.rs	🟢 93.41%	🟢 93.4%	🔴 -0.01%
brush-test-harness/src/execution.rs	🟢 79.26%	🟢 80.85%	🟢 1.59%
Overall Coverage	🟢 75.11%	🟢 74.94%	🔴 -0.17%

Minimum allowed coverage is 70%, this run produced 74.94%

Test Summary: bash-completion test suite

Outcome	Count	Percentage
✅ Pass	1580	74.92
❗️ Error	18	0.85
❌ Fail	157	7.44
⏩ Skip	339	16.07
❎ Expected Fail	13	0.62
✔️ Unexpected Pass	2	0.09
📊 Total	2109	100.00

[lu-zero]

sigh, probably would be easier to get it sorted once we use only the winnow parser.