Add support for new lines in main & arg doc

[jk-1]

Please add support for pre formatted text or at least support for

• new lines
• multiple spaces in the beginning of the line

in main(doc = "...") & arg(doc = "...").

They can increase help text readability and are especially important for presenting lists. Currently mainargs seems to filter away all multiple spaces and new line characters.

Example:

This is what I would like to see:

This program checks disk corruption for a LUKS-encrypted disk.

Steps:
  1. Ensures the provided device path is not already mounted.
  2. Opens the LUKS device using `cryptsetup luksOpen`.
  3. Verifies the disk mapping with `lsblk`.
  4. Runs `e2fsck` to check and repair the file system.
  5. Logs the operation details in a timestamped log file.

Example usage:
  lukse2fsck --devicePath /dev/sdb1 --mapperName usbbckpdev --backupName Backup_B4
  

but this is what I actually get:

This program checks disk corruption for a LUKS-encrypted disk. It performs the following steps: 1. Ensures the provided device path is not already mounted. 2. Opens the LUKS device using cryptsetup luksOpen. 3. Verifies the disk mapping with lsblk. 4. Runs e2fsck to check and repair the file system. 5. Logs the operation details in a timestamped log file. Example usage: lukse2fsck --devicePath /dev/sdb1 --mapperName usbbckpdev --backupName Backup_B4