docs: document why pre-commit language is set to 'local'

diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 329b09d4f8d4b85a25c44b64d0c0a3ef7cd45af6..082386b6786e9291b0ffaf70d2f6f30e5c673940 100644 (file)
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -1,4 +1,12 @@
 # See https://pre-commit.com for more information
+#
+# Note: we use `language: system` to make sure that pre-commit uses the same
+# dependencies installed by `pip install psycopg[dev]` and not some random
+# version installed in a hidden virtualenv. This way running the tools via
+# pre-commit should give the same result of running them manually.
+#
+# Please check README.rst about setting up a development env.
+
 repos:
   - repo: local
     hooks: