[DOCS] #4883 – Borg documentation downplays severity of Nonce reuse issue

Shorten the log info for deleting/keeping security info. Fix bad wording.

docs/faq.rst

@@ -202,9 +202,10 @@ the working repository to the same location:
 A plain delete command would remove the security info in
 ``~/.config/borg/security``, including the nonce value. In BorgBackup
 :ref:`security_encryption` is AES-CTR, where the nonce is a counter. When the
-working repo was used later for creating new archives, Borg would initialize a
-fresh nonce, which would be bad for security reasons. To prevent this, the
-``keep-security-info`` option is applied so that the nonce counter is kept.
+working repo was used later for creating new archives, Borg would re-use nonce
+values due to starting from a lower counter value given by the older copy of the
+repository. To prevent this, the ``keep-security-info`` option is applied so
+that the client-side nonce counter is kept.
 
 Can Borg add redundancy to the backup data to deal with hardware malfunction?
 -----------------------------------------------------------------------------

src/borg/archiver.py

@@ -1212,10 +1212,7 @@ class Archiver:
                     SecurityManager.destroy(repository)
             else:
                 logger.info("Would delete repository.")
-                if keep_security_info:
-                    logger.info("Would keep security info.")
-                else:
-                    logger.info("Would delete security info.")
+                logger.info("Would %s security info." % ("keep" if keep_security_info else "delete"))
         if not dry_run:
             Cache.destroy(repository)
             logger.info("Cache deleted.")
@@ -3359,7 +3356,7 @@ class Archiver:
         you run ``borg compact``.
 
         When you delete a complete repository, the security info and local cache for it
-        (if any) is also deleted. Alternatively, you can delete just the local cache
+        (if any) are also deleted. Alternatively, you can delete just the local cache
         with the ``--cache-only`` option, or keep the security info with the
         ``--keep-security-info`` option.