config: set __module__ = "pytest" on UsageError and ExitCode

These types occasionally get displayed by their qualified name, let's
make it nicer using the user-facing path.

Author: bluetech

src/_pytest/config/__init__.py

@@ -110,6 +110,8 @@ class ExitCode(enum.IntEnum):
     #: pytest couldn't find tests.
     NO_TESTS_COLLECTED = 5
 
+    __module__ = "pytest"
+
 
 class ConftestImportFailure(Exception):
     def __init__(

src/_pytest/config/exceptions.py

@@ -7,6 +7,8 @@
 class UsageError(Exception):
     """Error in pytest usage or invocation."""
 
+    __module__ = "pytest"
+
 
 class PrintHelp(Exception):
     """Raised when pytest should print its help to skip the rest of the