Document the return value of OSSL_LIB_CTX_load_config()

Reviewed-by: Paul Dale <pauli@openssl.org>
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/19101)

doc/man3/OSSL_LIB_CTX.pod

@@ -83,7 +83,7 @@ B<OSSL_provider_init> function returns then the new provider is available in the
 application's library context and will be similarly mirrored in the child
 library context.
 
-OSSL_LIB_CTX_load_config() loads a configuration file using the given C<ctx>.
+OSSL_LIB_CTX_load_config() loads a configuration file using the given I<ctx>.
 This can be used to associate a library context with providers that are loaded
 from a configuration.
 
@@ -118,6 +118,8 @@ on error.
 
 OSSL_LIB_CTX_free() doesn't return any value.
 
+OSSL_LIB_CTX_load_config() returns 1 on success, 0 on error.
+
 =head1 HISTORY
 
 All of the functions described on this page were added in OpenSSL 3.0.