ipamodule_base_docs: Documentation: Fix default for delete_continue

The default setting for delete_continue was True instead of true for
delete_continue in the DOCUMENTATION section.

plugins/doc_fragments/ipamodule_base_docs.py

@@ -56,5 +56,5 @@ options:
       Continuous mode. Don't stop on errors. Valid only if `state` is `absent`.
     aliases: ["continue"]
     type: bool
-    default: True
+    default: true
 """