Update recover_no_free_space_error.md

src/commands/forget/recover_no_free_space_error.md

@@ -6,23 +6,15 @@ such a way that a repository remains usable no matter at which point the command
 is interrupted. However, this also means that `prune` requires some scratch
 space to work.
 
-In most cases it is sufficient to instruct `prune` to use as little scratch
-space as possible by running it as `prune --max-repack-size 0`. Note that for
-rustic versions before 0.13.0 `prune --max-repack-size 1` must be used.
+In most cases it is sufficient to instruct `prune` to remove all packs marked for
+removal and use as little scratch space as possible.
+Note that packs marked for removal are automatically removed by a prune run once 
+they are old enough. If you can guarantee that the repository is not used by parallel
+processes, you can also use `rustic prune --instant-delete`.
+
+To use as little scratch space as possibe, run `rustic prune --max-repack-size 0`.
+This removes all unneeded packs without repacking partly used packs.
 Obviously, this can only work if several snapshots have been removed using
 `forget` before. This then allows the `prune` command to actually remove data
 from the repository. If the command succeeds, but there is still little free
 space, then remove a few more snapshots and run `prune` again.
-
-If `prune` fails to complete, then
-`prune --unsafe-recover-no-free-space SOME-ID` is available as a method of last
-resort. It allows prune to work with little to no free space. However, a
-**failed** `prune` run can cause the repository to become **temporarily
-unusable**. Therefore, make sure that you have a stable connection to the
-repository storage, before running this command. In case the command fails, it
-may become necessary to manually remove all files from the `index/` folder of
-the repository and run `rebuild-index` afterwards.
-
-To prevent accidental usages of the `--unsafe-recover-no-free-space` option it
-is necessary to first run `prune --unsafe-recover-no-free-space SOME-ID` and
-then replace `SOME-ID` with the requested ID.