Add caption to deciderule extlinks

It seems to be failing because the placeholder is missing:

```
  File "/home/docs/checkouts/readthedocs.org/user_builds/heritrix/envs/latest/lib/python3.12/site-packages/sphinx/ext/extlinks.py", line 103, in role
    title = caption % part
            ~~~~~~~~^~~~~~
TypeError: not all arguments converted during string formatting
```

Author: ato

docs/conf.py

@@ -160,5 +160,5 @@
 
 extlinks = {
     'deciderule': ('https://www.javadoc.io/doc/org.archive.heritrix/heritrix-modules/latest/org/archive/modules'
-                   '/deciderules/%s.html', '')
+                   '/deciderules/%s.html', 'DecideRule: %s')
 }