test(tests/examples/multiline.txt): 🚨 trim sample file to 10 lines to match new behavior
test(tests/integration_tests.rs): 🚨 adjust line ranges and expected outputs for 10-line sample; add multi-range context test
docs(CHANGELOG.md): 📚 add entry for context in line ranges and normalize list formatting
style(src/line_range.rs): 🎨 trim trailing whitespace in context parsing code
docs(long-help.txt): 📚 add examples for N::C and N:M:C context syntax
docs(clap_app.rs): 📚 update CLI help text with context syntax examples
feat(line_range.rs): ✨ implement N::C and N:M:C parsing and add tests
John Cavanaugh