doc: Fix typo in EVP_DigestSignInit manpage

CLA: trivial
Signed-off-by: NJakub Jelen <jjelen@redhat.com>
Reviewed-by: NRichard Levitte <levitte@openssl.org>
Reviewed-by: NTomas Mraz <tmraz@fedoraproject.org>
Reviewed-by: NMatt Caswell <matt@openssl.org>
Reviewed-by: NMatthias St. Pierre <Matthias.St.Pierre@ncp-e.com>
(Merged from https://github.com/openssl/openssl/pull/10841)

(cherry picked from commit 099a398268a298557be784528ac1d94f0f44c97c)

doc/man3/EVP_DigestSignInit.pod

@@ -102,7 +102,7 @@ EVP_DigestSignFinal().
 
 =head1 RETURN VALUES
 
-EVP_DigestSignInit(), EVP_DigestSignUpdate(), EVP_DigestSignaFinal() and
+EVP_DigestSignInit(), EVP_DigestSignUpdate(), EVP_DigestSignFinal() and
 EVP_DigestSign() return 1 for success and 0 for failure.
 
 The error codes can be obtained from L<ERR_get_error(3)>.