shred: remove the extension section

Author: sylvestre

docs/src/extensions.md

@@ -190,10 +190,6 @@ Similar to the proc-ps implementation and unlike GNU/Coreutils, `uptime` provide
 
 Just like on macOS, `base32/base64/basenc` provides `-D` to decode data.
 
-## `shred`
-
-The number of random passes is deterministic in both GNU and uutils. However, uutils `shred` computes the number of random passes in a simplified way, specifically `max(3, x / 10)`, which is very close but not identical to the number of random passes that GNU would do. This also satisfies an expectation that reasonable users might have, namely that the number of random passes increases monotonically with the number of passes overall; GNU `shred` violates this assumption.
-
 ## `unexpand`
 
 GNU `unexpand` provides `--first-only` to convert only leading sequences of blanks. We support a