reduce test verbosity

Write concise, efficient tests by eliminating repetitive code and combining related test cases. Avoid verbose patterns that can be simplified with better approaches.

Key strategies:

• Use multiline patterns instead of multiple screen:expect() calls with unchanged=true
• Write literal contents when known rather than using generic matchers like {MATCH: +}
• Combine related test cases into single tests when they save significant code (20+ lines)
• Create shared functions for tests that follow similar patterns
• Reuse existing test setup and assertions instead of creating new ones
• Keep validation tests concise - checking that a command requires an argument should only need ~2 lines

Example of verbose vs. concise screen testing:

-- Verbose (avoid):
screen:expect({ any = '.nvim.lua' })
screen:expect({ any = pesc('[i]gnore, (v)iew, (d)eny:'), unchanged = true })

-- Concise (prefer):
screen:expect({ any = 'Allowed.*\n.exrc' })

The goal is maintainable tests that clearly express intent without unnecessary repetition or complexity.