cargo fmt: three chains rustfmt splits

Formatting only. portable::instant (from F5), and the ffi's link and unlink
(F2/F3), were laid out by hand without a toolchain; rustfmt splits each chain.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

core/src/local/portable.rs

@@ -559,7 +559,9 @@ fn strings(v: Option<&Value>) -> Vec<String> {
 /// Any RFC 3339 instant, in the store's own form (UTC, milliseconds, `Z`). Anything
 /// else is treated as absent, as the server's `parse_dt` does.
 fn instant(raw: &str) -> Option<String> {
-    DateTime::parse_from_rfc3339(raw).ok().map(|t| iso(t.with_timezone(&Utc)))
+    DateTime::parse_from_rfc3339(raw)
+        .ok()
+        .map(|t| iso(t.with_timezone(&Utc)))
 }
 
 /// Keep's timestamps: integer microseconds since the epoch.