docs: Update Black and isort references to Ruff.

Signed-off-by: Anders Kaseorg <anders@zulip.com>

README.md

@@ -18,7 +18,6 @@ Come find us on the [development community chat](https://zulip.com/development-c
 [![coverage status](https://img.shields.io/codecov/c/github/zulip/zulip/main.svg)](https://codecov.io/gh/zulip/zulip)
 [![Mypy coverage](https://img.shields.io/badge/mypy-100%25-green.svg)][mypy-coverage]
 [![Ruff](https://img.shields.io/endpoint?url=https://raw.githubusercontent.com/astral-sh/ruff/main/assets/badge/v2.json)](https://github.com/astral-sh/ruff)
-[![code style: black](https://img.shields.io/badge/code%20style-black-000000.svg)](https://github.com/psf/black)
 [![code style: prettier](https://img.shields.io/badge/code_style-prettier-ff69b4.svg)](https://github.com/prettier/prettier)
 [![GitHub release](https://img.shields.io/github/release/zulip/zulip.svg)](https://github.com/zulip/zulip/releases/latest)
 [![docs](https://readthedocs.org/projects/zulip/badge/?version=latest)](https://zulip.readthedocs.io/en/latest/)

docs/contributing/code-style.md

@@ -61,9 +61,7 @@ lint checks in parallel, including:
 - JavaScript ([ESLint](https://eslint.org/),
   [Prettier](https://prettier.io/))
 - Python ([mypy](http://mypy-lang.org/),
-  [ruff](https://github.com/astral-sh/ruff),
-  [Black](https://github.com/psf/black),
-  [isort](https://pycqa.github.io/isort/))
+  [Ruff](https://docs.astral.sh/ruff/))
 - templates
 - Puppet configuration
 - custom checks (e.g., trailing whitespace and spaces-not-tabs)
@@ -139,15 +137,12 @@ rules about integrating third-party projects.
 ## Python-specific conventions and practices
 
 - Our Python code is formatted with
-  [Black](https://github.com/psf/black) and
-  [isort](https://pycqa.github.io/isort/). The [linter
-  tool](../testing/linters.md) enforces this by running Black and
-  isort in check mode, or in write mode with
-  `tools/lint --only=black,isort --fix`. You may find it helpful to
-  [integrate Black](https://black.readthedocs.io/en/stable/integrations/editors.html)
-  and
-  [isort](https://pycqa.github.io/isort/#installing-isorts-for-your-preferred-text-editor)
-  with your editor.
+  [Ruff](https://docs.astral.sh/ruff/). The [linter
+  tool](../testing/linters.md) enforces this by running Ruff in check
+  mode, or in write mode with
+  `tools/lint --only=ruff,ruff-format --fix`. You may find it helpful
+  to [integrate Ruff](https://docs.astral.sh/ruff/integrations/) with
+  your editor.
 - Don't put a shebang line on a Python file unless it's meaningful to
   run it as a script. (Some libraries can also be run as scripts, e.g.,
   to run a test suite.)

docs/testing/linters.md

@@ -23,14 +23,12 @@ prevent common coding errors.
 We borrow some open source tools for much of our linting, and the links
 below will direct you to the official documentation for these projects.
 
-- [Black](https://github.com/psf/black)
 - [ESLint](https://eslint.org)
-- [isort](https://pycqa.github.io/isort/)
 - [mypy](http://mypy-lang.org/)
 - [Prettier](https://prettier.io/)
 - [Puppet](https://puppet.com/) (puppet provides its own mechanism for
   validating manifests)
-- [ruff](https://github.com/astral-sh/ruff)
+- [Ruff](https://docs.astral.sh/ruff/)
 - [stylelint](https://github.com/stylelint/stylelint)
 
 Zulip also uses some home-grown code to perform tasks like validating
@@ -109,8 +107,8 @@ describes our test system in detail.
 Most of our lint checks get performed by `./tools/lint`. These include the
 following checks:
 
-- Check Python code with ruff.
-- Check Python formatting with Black and isort.
+- Check Python code with Ruff.
+- Check Python formatting with Ruff.
 - Check JavaScript and TypeScript code with ESLint.
 - Check CSS, JavaScript, TypeScript, and YAML formatting with Prettier.
 - Check Python code for custom Zulip rules.
@@ -131,7 +129,7 @@ The rest of this document pertains to the checks that occur in `./tools/lint`.
 
 Zulip has a script called `lint` that lives in our "tools" directory.
 It is the workhorse of our linting system, although in some cases it
-dispatches the heavy lifting to other components such as ruff,
+dispatches the heavy lifting to other components such as Ruff,
 eslint, and other home grown tools.
 
 You can find the source code [here](https://github.com/zulip/zulip/blob/main/tools/lint).
@@ -176,13 +174,12 @@ sense (e.g., a link in a comment to an extremely long URL).
 
 #### Python code
 
-Our Python code is formatted using Black (using the options in the
-`[tool.black]` section of `pyproject.toml`) and isort (using the
-options in `.isort.cfg`). The `lint` script enforces this by running
-Black and isort in check mode, or in write mode with `--fix`.
+Our Python code is formatted using
+[Ruff](https://docs.astral.sh/ruff/) (using the options in the
+`[tool.ruff]` section of `pyproject.toml`). The `lint` script enforces
+this by running Ruff in check mode, or in write mode with `--fix`.
 
-The bulk of our Python linting gets outsourced to the "ruff" tool,
-which is configured in the `tool.ruff` section of `pyproject.toml`.
+The bulk of our Python linting also gets outsourced to Ruff.
 
 Zulip also has custom regex-based rules that it applies to Python code.
 Look for `python_rules` in the source code for `lint`. Note that we

tools/setup/emoji/generate_emoji_names

@@ -214,7 +214,7 @@ def main() -> None:
         f.write("}\n")
 
     print(
-        "\n\nDone! You should run the linter to format emoji_names.py with `./tools/lint --fix -m --only black`"
+        "\n\nDone! You should run the linter to format emoji_names.py with `./tools/lint --fix -m --only ruff-format`"
     )