This reverts commit 65a333600d.
This wasn't tested for correctness with something like fodwatch [0],
and should not have been (self-)merged so quickly, especially without
further review.
It also resulted in the breakage of at least one package [1] (and that's
the one we know of and was caught).
A few packages that were updated in between this commit and this revert
were not reverted back to using `rev`, but other than that, this is a
1:1 revert.
[0]: https://codeberg.org/raphaelr/fodwatch
[1]: https://github.com/NixOS/nixpkgs/pull/396904 / 758551e458
GNU sed's man page has this to say about "-i":
Because -i takes an optional argument, it should not be followed by
other short options:
[..]
sed -iE '...' FILE
This is equivalent to --in-place=E, creating FILEE as backup of FILE
This means all "-iX" did not have the intended effect X, so we can
instead remove them.
