docs: explicitly specify plaintext format

src/certs/file_sscv.rs

@@ -13,8 +13,8 @@ pub struct KnownHostsFile {
 impl KnownHostsFile {
     /// Read or create a known_hosts file at the given path.
     /// Format of known_hosts is: _(fields are separated by any space sequence)_
-    /// ```
-    /// #host   expires    algo   base64 fingerprint
+    /// ```text
+    /// # host  expires    algo   base64 fingerprint
     /// dc09.ru 1722930541 sha512 dGVzdHRlc3R0ZXN0Cg
     /// ```
     pub async fn parse_file(path: impl AsRef<Path>) -> std::io::Result<KnownHostsFile> {