ext-exit documentation

[Yuri D'E. <wa...@th...>]

Just trying out the current main branch to play with the current version
of the --ext-exit option :). Thanks for considering this, it's quite
convenient to trigger local hooks.

The cli help looks fine in the source, but it's shifted when run:

  -y, --dry-run         do not actually modify anything
  -e, --ext-exit                return extended exit code

One tab too much.

The wording of the manual page is confusing IMHO.

| Return an extended exit code: Add 32 resp. 64 to the code if
                                ^^^^^^^^^^^^^^^^^^
I had to look at the sources to see what actually goes on.
Maybe rephrasing to:

"Add either 32 or 64 to the code if any modifications were made
respectively to the far side or near side. Both can apply at the same
time as well as error conditions so the code may be for example 65 if
some changes were successfully pulled, while others failed."