pw_software_update: Improve help strings

Testing: Changes are help-string only, but unit tests still pass
Change-Id: Iecbe056622c67854385c56697776bba97c98cfac
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/61782
Reviewed-by: Ali Zhang <alizhang@google.com>
Reviewed-by: David Rogers <davidrogers@google.com>
Commit-Queue: Joe Ethier <jethier@google.com>
diff --git a/pw_software_update/py/pw_software_update/update_bundle.py b/pw_software_update/py/pw_software_update/update_bundle.py
index e99f89d..58d9b9e 100644
--- a/pw_software_update/py/pw_software_update/update_bundle.py
+++ b/pw_software_update/py/pw_software_update/update_bundle.py
@@ -11,7 +11,7 @@
 # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 # License for the specific language governing permissions and limitations under
 # the License.
-"""Facilities for generating and serializing update bundles."""
+"""Generate and serialize update bundles."""
 
 import argparse
 import logging
@@ -116,13 +116,13 @@
                         type=Path,
                         nargs='+',
                         default=tuple(),
-                        help='Exclude a path from the TUF repository')
+                        help='Exclude paths from the TUF repository')
     parser.add_argument('-r',
                         '--remap',
                         type=str,
                         nargs='+',
                         default=tuple(),
-                        help='Remap a path to a custom target file name')
+                        help='Remap paths to custom target file names')
     return parser.parse_args()