document new-version's --bug argument

Provide examples of using the --bug argument in the --help text and man
page.

Change-Id: Ie0120f857a24c17032862472f1fca150f43f3f91

Author: ktdreyer

doc/rdopkg.1.adoc

@@ -153,6 +153,18 @@ much like `rpmdev-bumpspec`:
 
     rdopkg -bn
 
+To note particular bugs in the changelog, use the `-B`/`--bug` option. rdopkg
+will append the supplied string to changelog in brackets. For example:
+
+    rdopkg new-version --bug rhbz#1234,rhbz#5678
+
+will result in following %changelog line:
+
+    Update to 1.1.1 (rhbz#1234,rhbz#5678)
+
+and corresponding `Resolves:` lines in commit message.
+
+
 *Flow:*
 
   * Show diff from previous version, especially changes to `requirements.txt`.

rdopkg/actions/distgit/__init__.py

@@ -111,7 +111,8 @@
                Arg('no_push_patches', shortcut='-t', action='store_true',
                    help="don't push patches branch"),
                Arg('bug', shortcut='-B', metavar='BUG(S)',
-                   help="reference BUG(S) in changelog"),
+                   help="reference BUG(S) in changelog. (example:"
+                        " --bug rhbz#1234,rhbz#5678)"),
            ],
            steps=[
                Action('get_package_env'),