Typer

* Add support for `help` parameter in *CLI arguments*:
* As `help` in *CLI arguments* is not supported by Click, there are two new internal classes (Click sub-classes) to support it:
* `typer.core.TyperArgument`
* `typer.core.TyperCommand`
* This includes a new auto-generated help text section `Arguments` for *CLI arguments*, showing defaults, required arguments, etc.
* It's also possible to disable it and keep the previous behavior, not showing automatic help for *CLI arguments* (Click's default) using the `hidden` parameter.
* Now `show_default` is `True` by default.
* And now `show_envvar` is `True` by default.
* So, default values and env vars are shown in the help text by default, without having to manually enable them, for both *CLI arguments* and *CLI options*.
* New docs:
* [CLI Arguments Intro](https://typer.tiangolo.com/tutorial/arguments/).
* [Optional CLI Arguments](https://typer.tiangolo.com/tutorial/arguments/optional/).
* [CLI Arguments with Default](https://typer.tiangolo.com/tutorial/arguments/default/).
* [CLI Arguments with Help](https://typer.tiangolo.com/tutorial/arguments/help/).
* [CLI Arguments with Environment Variables](https://typer.tiangolo.com/tutorial/arguments/envvar/).
* [CLI Arguments: Other uses](https://typer.tiangolo.com/tutorial/arguments/other-uses/).
* [CLI arguments with tuples](https://typer.tiangolo.com/tutorial/multiple-values/arguments-with-multiple-values/#cli-arguments-with-tuples).
* Lot's of tests for all the new examples in the new docs, keeping coverage at 100%.
* PR [123](https://github.com/tiangolo/typer/pull/123).
* Add docs for calling packages with `python -m some_package` using `__main__.py`: [Building a Package: Support `python -m`](https://typer.tiangolo.com/tutorial/package/#support-python-m-optional). PR [121](https://github.com/tiangolo/typer/pull/121).
* Add support for `*args` and `**kwargs` when calling the Typer app, just like in Click. PR [120](https://github.com/tiangolo/typer/pull/120) by [teymour-aldridge](https://github.com/teymour-aldridge).
* Fix typos in README and main docs [103](https://github.com/tiangolo/typer/pull/103) by [mrcartoonster](https://github.com/mrcartoonster).
* Fix typo in docs. PR [98](https://github.com/tiangolo/typer/pull/98) by [mrcartoonster](https://github.com/mrcartoonster).
* Fix typos and rewording in docs. PR [97](https://github.com/tiangolo/typer/pull/97) by [mrcartoonster](https://github.com/mrcartoonster).
* Update GitHub Action issue-manager. PR [114](https://github.com/tiangolo/typer/pull/114).

* Add support for forward references (types declared inside of strings). PR [93](https://github.com/tiangolo/typer/pull/93).

* Add support for completion for commands/programs not available on startup.
* This allows installing a Typer program/script in a virtual environment and still have completion globally installed.
* PR [92](https://github.com/tiangolo/typer/pull/92).
* Add note about `typer.echo()` and `print()` for colors in Windows. PR [89](https://github.com/tiangolo/typer/pull/89).
* Upgrade Mkdocs-Material version, update contributing guide style. PR [90](https://github.com/tiangolo/typer/pull/90).

* Fix completion evaluation for Bash and Zsh when the program is not installed/found. PR [83](https://github.com/tiangolo/typer/pull/83).
* Fix completion script for Fish. PR [82](https://github.com/tiangolo/typer/pull/82).
* Fix shell installation for Bash to `~/.bashrc` and update Windows development docs. PR [81](https://github.com/tiangolo/typer/pull/81).
* Update coverage badge. PR [78](https://github.com/tiangolo/typer/pull/78).

* Fix coverage instructions. PR [72](https://github.com/tiangolo/typer/pull/72).
* Add docs for [Building a Package](https://typer.tiangolo.com/tutorial/package/). PR [#71](https://github.com/tiangolo/typer/pull/71).
* Add docs for [Using Click (with Typer)](https://typer.tiangolo.com/tutorial/using-click/). PR [#70](https://github.com/tiangolo/typer/pull/70).
* Add support for type-based callbacks and autocompletion functions, extra tests and docs:
* Extra tests, raising coverage to 100%.
* New docs: [Printing and Colors: "Standard Output" and "Standard Error"](https://typer.tiangolo.com/tutorial/printing/#standard-output-and-standard-error).
* New docs: [Password CLI Option and Confirmation Prompt](https://typer.tiangolo.com/tutorial/options/password/).
* Support for callbacks based on type annotations. New docs: [CLI Option Callback and Context](https://typer.tiangolo.com/tutorial/options/callback-and-context/).
* New docs: [Version CLI Option, is_eager](https://typer.tiangolo.com/tutorial/options/version/).
* Support for autocompletion functions based on type annotations. New docs: [CLI Option autocompletion](https://typer.tiangolo.com/tutorial/options/autocompletion/).
* New docs: [Commands: Using the Context](https://typer.tiangolo.com/tutorial/commands/context/).
* New docs: [Testing](https://typer.tiangolo.com/tutorial/testing/).
* PR [68](https://github.com/tiangolo/typer/pull/68).
* Fix Zsh completion install script. PR [69](https://github.com/tiangolo/typer/pull/69).
* Fix typo in progressbar example. PR [63](https://github.com/tiangolo/typer/pull/63) by [ValentinCalomme](https://github.com/ValentinCalomme).

* Re-implement completion system:
* Remove optional dependency `click-completion` (with its sub-dependencies, like Jinja).
* Add optional dependency `shellingham` to auto detect shell to install (it was used by `click-completion`).
* Completion now doesn't require a third party library.
* If `shellingham` is not installed/added as a dependency, `--install-completion` and `--show-completion` take a value with the name of the shell.
* Fix support for user provided completion in *CLI Parameters*.
* Fix completion for files in Bash, Zsh, and Fish.
* Add support for modern versions of PowerShell, 5, 6, and 7 (e.g. in Windows 10).
* Add support for `pwsh` (PowerShell Core).
* PowerShell support includes help strings for commands and *CLI Parameters*.
* Several bug fixes.
* Tests for the completion logic/code.
* Tested in all the shells in Linux and Windows.
* PR [66](https://github.com/tiangolo/typer/pull/66).
* Fix format in docs with highlighted lines. PR [65](https://github.com/tiangolo/typer/pull/65).
* Add docs about [Typer CLI - completion for small scripts](https://typer.tiangolo.com/typer-cli/). PR [#64](https://github.com/tiangolo/typer/pull/64).
* Add docs about [Alternatives, Inspiration and Comparisons](https://typer.tiangolo.com/alternatives/). PR [#62](https://github.com/tiangolo/typer/pull/62).
* Add [Development - Contributing Guide](https://typer.tiangolo.com/contributing/). PR [#61](https://github.com/tiangolo/typer/pull/61).