Add glossary of terms to documentation

[by22Jy]

Summary

Adds a glossary section to Click's documentation defining key terms used throughout the docs.

Changes

• Added docs/glossary.rst with definitions for 10 key terms
• Updated docs/index.rst to include the glossary in General Reference section

Terms Defined

• Argument: Positional parameter passed to a command
• Callback: Function invoked when a parameter is processed
• Command: Function decorated with @click.command() or @click.group()
• Command Line Interface (CLI): Text-based interface for program interaction
• Context: Object carrying state between commands
• Flag: Boolean option without a value
• Group: Command containing subcommands
• Multi-command: Command grouping multiple subcommands
• Option: Named parameter with dash prefix
• Parameter: General term for options and arguments

Closes #3077

Checklist

• Documentation builds correctly
• Follows existing documentation style
• Terms are clear and consistent with Click's usage

[nrschroeder]

This looks good ... the glossary seems like it will make the docs a lot clearer.

One thing I noticed while reading the issue is that it also mentioned terms like “terminal”, “command line application”, and “command line utility”. Since those show up in different places in the docs as well, it might be helpful to include them here too for completeness.

[by22Jy]

Hi @nrschroeder, thank you for the great suggestion! I've added the three additional terms you mentioned:

• Terminal: A text-based interface for interacting with the operating system
• Command Line Application: A Python program built with Click that provides a CLI
• Command Line Utility: A command line application designed to perform specific tasks

These terms will definitely help make the documentation more comprehensive. Let me know if you'd like any adjustments to the definitions!