docs: quote placeholders in shell examples so the blocks paste safely An unquoted <placeholder> inside a shell-tagged fence is redirection from a file of that name, so a copied command aborts (exit 1), fails to parse (exit 2), or — where it sits mid-block — is silently skipped while the block still reports exit 0. Quote the placeholder, which keeps it visible as a placeholder and passes it through verbatim. Usage synopses are left alone: where a fence carries [...] optional-argument notation, or a placeholder fills a command slot, the <> is grammar for the command's shape rather than a command to paste. Fixes #2196

Add versioned docs for v2.1 (#1903) Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>