Remove deprecated pre-commit script (#6455)

CONTRIBUTING.md

@@ -24,14 +24,23 @@ it takes a bit longer. For more details, read below.
 
 ## Preparing the environment
 
-To reformat the code, check for common problems, and
-run the tests, it can be useful to prepare a
-[virtual environment](https://docs.python.org/3/tutorial/venv.html) and install
-certain libraries typeshed uses to check stub files.
+### Code away!
 
-Follow platform-specific instructions below. Following that, to automatically
-check your code before committing, you can copy the file `pre-commit` to
-`.git/hooks/pre-commit`.
+Typeshed runs continuous integration (CI) on all pull requests. This will
+automatically fix formatting (using `black`, `isort`) and run tests.
+It means you can ignore all local setup on your side, focus on the
+code and rely on the CI to fix everything, or point you to the places that
+need fixing.
+
+### ... Or create a local development environment
+
+If you prefer to run the tests & formatting locally, it's
+possible too. Follow platform-specific instructions below.
+
+Whichever platform you're using, you will need a
+virtual environment. If you're not familiar with what it is and how it works,
+please refer to this
+[documentation](https://packaging.python.org/guides/installing-using-pip-and-virtual-environments/).
 
 ### Linux/Mac OS
 
@@ -74,6 +83,19 @@ following commands from a Windows terminal:
 (.venv3) > python -m pip install -r requirements-tests-py3.txt
 ```
 
+## Code formatting
+
+The code is formatted by `black` and `isort`.
+
+The repository is equipped with a [`pre-commit.ci`](https://pre-commit.ci/)
+configuration file. This means that you don't *need* to do anything yourself to
+run the code formatters. When you push a commit, a bot will run those for you
+right away and add a commit to your PR. Neat, no?
+
+That being said, if you *want* to run the checks locally when you commit, you
+can install the hooks: please refer to the [pre-commit](https://pre-commit.com/)
+documentation.
+
 ## Where to make changes
 
 ### Standard library stubs

pre-commit

@@ -1,28 +0,0 @@
-#!/bin/sh
-#
-# An example hook script that will run flake8, black, and isort
-# prior to committing and will stop the commit if there are any
-# warnings. Adjust BIN_DIR to the virtual environment where flake8,
-# black, and isort are installed.
-#
-# To enable this hook, copy this file to ".git/hooks".
-
-BIN_DIR=./.venv3/bin
-
-CHANGED_FILES=$(git diff --cached --name-only --diff-filter=AM | grep .pyi || true)
-
-if test -n "${CHANGED_FILES}" -a -d "${BIN_DIR}"; then
-    ${BIN_DIR}/flake8 ${CHANGED_FILES}
-    ${BIN_DIR}/black --check ${CHANGED_FILES}
-    ${BIN_DIR}/isort --check-only ${CHANGED_FILES}
-
-    # Replace the last two lines with the following lines
-    # if you want to reformat changed files automatically
-    # before committing. Please note that partial commits
-    # (git add -p) will not work and will commit the whole
-    # file!
-    #
-    # ${BIN_DIR}/black ${CHANGED_FILES} || true
-    # ${BIN_DIR}/isort -y ${CHANGED_FILES} || true
-    # git add ${CHANGED_FILES}
-fi