Fixed typo in X509_STORE_CTX_new description

 'X509_XTORE_CTX_cleanup' ->  'X509_STORE_CTX_cleanup'
Reviewed-by: Kurt Roeckx <kurt@openssl.org>
Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/3271)
(cherry picked from commit 7643a172)