Load SSL's error strings in hashlib.

Without ERR_load_crypto_strings() functions like ERR_lib_error_string() return NULL.

Misc/NEWS

@@ -16,6 +16,8 @@ Core and Builtins
 Library
 -------
 
+- Load SSL's error strings in hashlib.
+
 - Issue #18527: Upgrade internal copy of zlib to 1.2.8.
 
 - Issue #19274: Add a filterfunc parameter to PyZipFile.writepy.

Modules/_hashopenssl.c

@@ -847,6 +847,7 @@ PyInit__hashlib(void)
     PyObject *m, *openssl_md_meth_names;
 
     OpenSSL_add_all_digests();
+    ERR_load_crypto_strings();
 
     /* TODO build EVP_functions openssl_* entries dynamically based
      * on what hashes are supported rather than listing many