* unexpand: should allow multiple files #5852 and unexpand: show error message if a directory is specified #5845
* test file added for #5845#5852
* test case test_multiple_files improve
* cakebaker suggestion for a better code #5845#5852
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Co-authored-by: biplab5464 <biplab5464@outlook.com>
* feat: move unexpand to clap
* chore: allow muliple files
* test: add test fixture, test reading from a file
* test: fix typo on file name, add test for multiple inputs
* chore: use 'success()' instead of asserting
* chore: delete unused variables
* chore: use help instead of long_help, break long line