fix: keep write_usage output for commands without args

[d3v07]

Fixes #3360

HelpFormatter.write_usage() routed empty args through the text wrapper, which produced an empty line and dropped the usage prefix entirely. Handle the no-args case directly so Usage: <prog> still renders for internal commands that take no arguments.

This adds a regression test for HelpFormatter.write_usage("program") and updates CHANGES.rst.

Verification

• PYTHONPATH=src .venv/bin/pytest tests/test_formatting.py -q

[Copilot]

Pull request overview

Fixes Click’s HelpFormatter.write_usage() behavior when called with no args, ensuring the “Usage:” prefix and program name are still emitted (regression for internal/interactive commands with no arguments).

Changes:

• Update HelpFormatter.write_usage() to handle the no-args case without routing through the text wrapper.
• Add a regression test for write_usage("program") with default args.
• Document the fix in CHANGES.rst under 8.3.3.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
src/click/formatting.py	Adds an early-return path to reliably render Usage: <prog> when args is empty.
tests/test_formatting.py	Adds a regression test asserting Usage: program\n for no-args usage rendering.
CHANGES.rst	Notes the bugfix and links to issue #3360.

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[Copilot]

For consistency within this test module, consider instantiating the formatter via the public alias click.HelpFormatter() (used in test_help_formatter_write_text) instead of reaching into click.formatting.HelpFormatter(). This keeps tests aligned with the intended public API surface.

Suggested change

	formatter = click.formatting.HelpFormatter()
	formatter = click.HelpFormatter()