Replace ZoL with OpenZFS where applicable

Afterward, git grep ZoL matches:
  * README.md:  * [ZoL Site](https://zfsonlinux.org)
  - Correct
  * etc/default/zfs.in:# ZoL userland configuration.
  - Changing this would induce a needless upgrade-check,
    if the user has modified the configuration;
    this can be updated the next time the defaults change
  * module/zfs/dmu_send.c:   * ZoL < 0.7 does not handle [...]
  - Before 0.7 is ZoL, so fair enough

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Issue #11956

module/icp/algs/edonr/edonr.c

@@ -337,7 +337,7 @@ Q256(size_t bitlen, const uint32_t *data, uint32_t *restrict p)
  *
  * Checksum functions like this one can go over the stack frame size check
  * Linux imposes on 32-bit platforms (-Wframe-larger-than=1024).  We can
- * safely ignore the compiler error since we know that in ZoL, that
+ * safely ignore the compiler error since we know that in OpenZFS, that
  * the function will be called from a worker thread that won't be using
  * much stack.  The only function that goes over the 1k limit is Q512(),
  * which only goes over it by a hair (1248 bytes on ARM32).