Update EVP_PKEY documentation.

Add EVP_PKEY_up_ref() documentation and fix various typos.
Reviewed-by: NViktor Dukhovni <viktor@openssl.org>

doc/crypto/EVP_PKEY_new.pod

@@ -2,40 +2,42 @@
 
 =head1 NAME
 
-EVP_PKEY_new, EVP_PKEY_free - private key allocation functions.
+EVP_PKEY_new, EVP_PKEY_up_ref, EVP_PKEY_free - private key allocation functions.
 
 =head1 SYNOPSIS
 
  #include <openssl/evp.h>
 
  EVP_PKEY *EVP_PKEY_new(void);
+ void EVP_PKEY_up_ref(EVP_PKEY *key);
  void EVP_PKEY_free(EVP_PKEY *key);
 
 
 =head1 DESCRIPTION
 
-The EVP_PKEY_new() function allocates an empty B<EVP_PKEY> 
-structure which is used by OpenSSL to store private keys.
+The EVP_PKEY_new() function allocates an empty B<EVP_PKEY> structure which is
+used by OpenSSL to store private keys. The reference count is set to B<1>.
 
-EVP_PKEY_free() frees up the private key B<key>.
-If B<key> is NULL, nothing is done.
+EVP_PKEY_up_ref() increments the reference count of B<key>.
+
+EVP_PKEY_free() decrements the reference count of B<key> and, if the reference
+count is zero, frees it up. If B<key> is NULL, nothing is done.
 
 =head1 NOTES
 
-The B<EVP_PKEY> structure is used by various OpenSSL functions
-which require a general private key without reference to any
-particular algorithm.
+The B<EVP_PKEY> structure is used by various OpenSSL functions which require a
+general private key without reference to any particular algorithm.
 
-The structure returned by EVP_PKEY_new() is empty. To add a
-private key to this empty structure the functions described in
-L<EVP_PKEY_set1_RSA(3)> should be used.
+The structure returned by EVP_PKEY_new() is empty. To add a private key to this
+empty structure the functions described in L<EVP_PKEY_set1_RSA(3)> should be
+used.
 
 =head1 RETURN VALUES
 
-EVP_PKEY_new() returns either the newly allocated B<EVP_PKEY>
-structure of B<NULL> if an error occurred.
+EVP_PKEY_new() returns either the newly allocated B<EVP_PKEY> structure or
+B<NULL> if an error occurred.
 
-EVP_PKEY_free() does not return a value.
+EVP_PKEY_up_ref() and EVP_PKEY_free() do not return a value.
 
 =head1 SEE ALSO
 
@@ -43,6 +45,8 @@ L<EVP_PKEY_set1_RSA(3)>
 
 =head1 HISTORY
 
-TBA
+EVP_PKEY_new() and EVP_PKEY_free() exist in all versions of OpenSSL.
+
+EVP_PKEY_up_ref() was first added to OpenSSL 1.1.0.
 
 =cut