docs: update dsync option for deleting destination files

    - update no-delete option to delete-dst option, which will
      delete extraneous files in the destination directory

doc/rst/dsync.1.rst

@@ -11,9 +11,9 @@ DESCRIPTION
 
 Parallel MPI application to synchronize two files or two directory trees.
 
-dsync makes DEST match SRC, adding missing entries from DEST, removing
-extra entries from DEST, and updating existing entries in DEST as necessary
-so that SRC and DEST have identical content, ownership, timestamps, and permissions.
+dsync makes DEST match SRC, adding missing entries from DEST, and updating
+existing entries in DEST as necessary so that SRC and DEST have identical
+content, ownership, timestamps, and permissions.
 
 OPTIONS
 -------
@@ -31,9 +31,9 @@ OPTIONS
    Compare files byte-by-byte rather than checking size and mtime
    to determine whether file contents are different.
 
-.. option:: -N, --no-delete
+.. option:: -D, --delete-dst
 
-   Do not delete extraneous files from destination.
+   Delete extraneous files from destination.
 
 .. option:: -v, --verbose