Don't mention pk_sign() in the context of public-key contexts
diff --git a/include/mbedtls/x509_crt.h b/include/mbedtls/x509_crt.h
index 293a710..6db9bc9 100644
--- a/include/mbedtls/x509_crt.h
+++ b/include/mbedtls/x509_crt.h
@@ -904,8 +904,8 @@
* in a thread-safe way. In particular, the caller must only
* use the context with functions which are `const` on the input
* context, or those which are known to be thread-safe. The latter
- * for example includes mbedtls_pk_sign() and mbedtls_pk_verify()
- * for ECC or RSA public key contexts.
+ * for example includes mbedtls_pk_verify() for ECC or RSA public
+ * key contexts.
*
* \return \c 0 on success. In this case, `*pk_ptr` is updated
* to hold the address of a public key context for the given