docs: improve

docs/release_notes.rst

@@ -50,6 +50,8 @@ v15.4.0
    rather than fork, since this is method is more robust and avoids some
    issues when threads are present.
 -  Fixed an instance where the user's request to ``--no-use-threads`` was ignored.
+-  If a PDF does not have language metadata on its top level object, we add
+   the OCR language.
 -  Replace some cryptic test error messages with more helpful ones.
 -  Debug messages for how OCRmyPDF picks the colorspace for a page are now
    more descriptive.

src/ocrmypdf/_pipelines/_common.py

@@ -229,7 +229,17 @@ def cli_exception_handler(
     options: argparse.Namespace,
     plugin_manager: OcrmypdfPluginManager,
 ) -> ExitCode:
+    """Convert exceptions into command line error messages and exit codes.
+
+    When known exceptions are raised, the exception message is printed to stderr
+    and the program exits with a non-zero exit code. When unknown exceptions are
+    raised, the exception traceback is printed to stderr and the program exits
+    with a non-zero exit code.
+    """
     try:
+        # We cannot use a generator and yield here, as would be the usual pattern
+        # for exception handling context managers, because we need to return an exit
+        # code.
         return fn(options, plugin_manager)
     except KeyboardInterrupt:
         if options.verbose >= 1: