feat(help): add detailed usage instructions and help flag to merge-pull-requests-by-title.sh

[joshjohanning]

Adding a --help flag to help with input options

[Copilot]

Pull request overview

Adds a dedicated --help/-h flow to gh-cli/merge-pull-requests-by-title.sh so users can discover supported invocation modes, positional args, and flags directly from the script.

Changes:

• Introduces a print_help() function with detailed usage/flags/examples
• Adds -h / --help handling to exit early after printing help
• Replaces the “too few args” usage block with a print_help call

Comments suppressed due to low confidence (1)

gh-cli/merge-pull-requests-by-title.sh:154

• The argument parser only errors on unknown long options (--*). With -h now supported, other unknown short options (e.g., -x) will be treated as positional args and can lead to confusing failures later. Consider explicitly rejecting unknown -* flags (or supporting -- end-of-options) and showing the valid flags/help output.

while [ $i -lt ${#args[@]} ]; do
  arg="${args[$i]}"
  if [ "$arg" = "--help" ] || [ "$arg" = "-h" ]; then
    print_help
    exit 0
  elif [ "$arg" = "--dry-run" ]; then
    dry_run=true
  elif [ "$arg" = "--bump-patch-version" ]; then
    bump_patch_version=true
  elif [ "$arg" = "--enable-auto-merge" ]; then
    enable_auto_merge=true
  elif [ "$arg" = "--no-prompt" ]; then
    no_prompt=true
  elif [ "$arg" = "--owner" ]; then
    ((i++))
    search_owner="${args[$i]}"
    if [ -z "$search_owner" ] || [[ "$search_owner" == --* ]]; then
      echo "Error: --owner requires a value"
      exit 1
    fi
    if ! [[ "$search_owner" =~ ^[a-zA-Z0-9._-]+$ ]]; then
      echo "Error: Invalid owner '$search_owner' - must be a valid GitHub username or organization"
      exit 1
    fi
  elif [ "$arg" = "--topic" ]; then
    ((i++))
    topic_val="${args[$i]}"
    if [ -z "$topic_val" ] || [[ "$topic_val" == --* ]]; then
      echo "Error: --topic requires a value"
      exit 1
    fi
    topics+=("$topic_val")
  elif [[ "$arg" == --* ]]; then
    echo "Error: Unknown flag '$arg'"
    echo "Valid flags: ${valid_flags[*]}"
    exit 1
  fi