Add renaming advice based on IETF draft-knodel-terminology-00

Add a new "usage" dictionary with usage advice based on:
https://tools.ietf.org/id/draft-knodel-terminology-00.html#rfc.section.1.1.1

Offer to replace master/slave with:
- Primary-secondary
- Leader-follower
- Active-standby
- Primary-replica
- Writer-reader
- Coordinator-worker
- Parent-helper

codespell_lib/_codespell.py

@@ -43,6 +43,7 @@
     ('clear', 'for unambiguous errors', '', False, None),
     ('rare', 'for rare but valid words', '_rare', None, None),
     ('informal', 'for informal words', '_informal', True, True),
+    ('usage', 'for recommended terms', '_usage', False, False),
     ('code', 'for words common to code and/or mathematics', '_code', None, None),  # noqa: E501
     ('names', 'for valid proper names that might be typos', '_names', None, None),  # noqa: E501
     ('en-GB_to_en-US', 'for corrections from en-GB to en-US', '_en-GB_to_en-US', True, True),  # noqa: E501

codespell_lib/data/dictionary_usage.txt

@@ -0,0 +1,4 @@
+master->primary, leader, active, writer, coordinator, parent,
+masters->primaries, leaders, actives, writers, coordinators, parents,
+slave->secondary, follower, standby, replica, reader, worker, helper,
+slaves->secondaries, followers, standbys, replicas, readers, workers, helpers,

codespell_lib/tests/test_dictionary.py

@@ -175,6 +175,8 @@ def test_error_checking_in_aspell(err, rep, err_aspell, rep_aspell, match):
 allowed_dups = {
     ('dictionary.txt', 'dictionary_en-GB_to_en-US.txt'),
     ('dictionary.txt', 'dictionary_rare.txt'),
+    ('dictionary.txt', 'dictionary_usage.txt'),
+    ('dictionary_rare.txt', 'dictionary_usage.txt'),
 }