Added a comment on when deprecated behavior can be removed (#12938)

Author: alex

src/rust/src/x509/certificate.rs

@@ -477,6 +477,7 @@ fn parse_display_text<'p>(
         DisplayText::IA5String(o) => Ok(pyo3::types::PyString::new(py, o.as_str()).into_any()),
         DisplayText::Utf8String(o) => Ok(pyo3::types::PyString::new(py, o.as_str()).into_any()),
         DisplayText::VisibleString(o) => {
+            // We should be able to remove this at the start of 2027.
             if asn1::VisibleString::new(o.as_str()).is_none() {
                 let warning_cls = types::DEPRECATED_IN_41.get(py)?;
                 let message = cstr_from_literal!("Invalid ASN.1 (UTF-8 characters in a VisibleString) in the explicit text and/or notice reference of the certificate policies extension. In a future version of cryptography, an exception will be raised.");