start testing on 3.14 and 3.14t (#929)

Author: Carreau

.github/workflows/tests.yml

@@ -24,7 +24,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest, windows-latest, macos-latest]
-        python-version: ["3.9", "3.13"]
+        python-version: ["3.9", "3.13", "3.14", "3.14t"]
         include:
           - os: ubuntu-latest
             python-version: "3.10"

traitlets/config/application.py

@@ -215,7 +215,8 @@ def _classes_inc_parents(
     _log_formatter_cls = LevelFormatter
 
     log_datefmt = Unicode(
-        "%Y-%m-%d %H:%M:%S", help="The date format used by logging formatters for %(asctime)s"
+        "%Y-%m-%d %H:%M:%S",
+        help="The date format used by logging formatters for `asctime`",
     ).tag(config=True)
 
     log_format = Unicode(