meta_payable_documentation: Bugfix which metadata we're checking.

Checking approval/contract was in the original specification,
looking at invoice instead of approval was a pure brain fart.

conservancy_beancount/plugin/meta_payable_documentation.py

@@ -23,7 +23,7 @@ from ..beancount_types import (
 )
 
 class MetaPayableDocumentation(core._RequireLinksPostingMetadataHook):
-    CHECKED_METADATA = ['invoice', 'contract']
+    CHECKED_METADATA = ['approval', 'contract']
 
     def _run_on_post(self, txn: Transaction, post: data.Posting) -> bool:
         if post.account.is_under('Liabilities:Payable'):

tests/test_meta_payable_documentation.py

@@ -29,20 +29,20 @@ ACCOUNTS = [
 ]
 
 SUPPORTING_METADATA = [
+    'approval',
     'contract',
-    'invoice',
 ]
 
 NON_SUPPORTING_METADATA = [
-    'approval',
     'check',
+    'invoice',
     'purchase-order',
     'receipt',
     'statement',
 ]
 
 OTHER_ACCT = 'Expenses:Other'
-MISSING_MSG = f"{{}} missing invoice/contract".format
+MISSING_MSG = f"{{}} missing approval/contract".format
 
 # for supporting links, use the lists from testutil