feat: start sops edit on the key's line

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

docs/repos.md

@@ -77,7 +77,9 @@ KMS, PGP). When sops can't decrypt, its whole error message is shown.
   without either, in the system's default app for the file.
 
 Editors that take a line (vim, nvim, nano, emacs, micro, helix, VS Code,
-Zed, Sublime and others) start on the key.
+Zed, Sublime and others) start on the key. With `sops edit` that works for
+editors taking `+N` (vim, nvim, nano, emacs, micro and others), and needs
+sops 3.8 or later.
 
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