docs: n34 book

Signed-off-by: Awiteb <a@4rs.nl>

docs/sets/update.md

@@ -0,0 +1,25 @@
+# Modify a Set
+
+> `n34 sets update` command
+
+**Usage:**
+```
+Modify an existing set
+
+Usage: n34 sets update [OPTIONS] <NAME>
+
+Arguments:
+  <NAME>  Name of the set to update
+
+Options:
+      --set-relay <RELAYS>         Add relay to the set, either as URL or set name to extract its relays. [aliases: `--sr`]
+      --repo <NADDR-NIP05-OR-SET>  Repository address in `naddr` format (`naddr1...`), NIP-05 format (`4rs.nl/n34` or `_@4rs.nl/n34`), or a set name like `kernel`
+      --override                   Replace existing relays/repositories instead of adding to them
+```
+
+Use this command to update an existing set by its name. By default, providing
+relays via `--set-relay` or repositories via `--repo` will add them to the set's
+existing entries. To replace the current relays and repositories with the new
+values, use the `--override` flag.
+
+[passing repositories]: /commands.html#passing-repositories