[llvm-dwarfdump][docs] Add missing options to the help output and the command guide

This change is to add some missing details to the help text and command
guide:

- Added a note to the command guide that --debug-macro also dumps
  .debug_macinfo.
- Added a note to the command guide that --debug-frame and --eh_frame
  are aliases, and in cases where both sections are present one command
  outputs both.
- Changed the wording in the help output for --ignore-case and --regex to
  closer match the command guide.