Enable all ruff's linting rules

I do like to be notified if I leave an unused import in my code, so I
tried adding the F401 rule to my Makefile.

It flagged the unused import of `page` into `wpsite`, which was there to
make the `page` module importable in tests with:

    from .context import page

Unused imports can be silenced by defining `__all__`, so it made sense
to squash that by listing the modules in `__all__`. However, given that
I included the import for testing purposes, why not move the fix to the
test setup?

So I've explicitly imported all tested modules in `tests/context.py`
instead.

I then realised that I was only one step away from enabling all of
ruff's linting rules; ignoring E402 which complains if module-level
imports aren't at the top of the file. That was easily fixed with a
quick:

    ruff check --add-noqa .

Makefile

@@ -3,7 +3,7 @@ check: lint format types
 
 .PHONY: lint
 lint:
-	ruff check . --select E9,F63,F7,F82 --show-source
+	ruff check .  --show-source
 
 .PHONY: format
 format:

tests/context.py

@@ -1,10 +1,14 @@
+__all__ = ['astro', 'page', 'wp']
+
 import os
 import sys
 
 project_root = os.path.abspath(os.path.join(os.path.dirname(__file__), '..'))
 sys.path.insert(0, project_root)
 
-from wpsite import *
+from wpsite import astro  # noqa: E402
+from wpsite import page  # noqa: E402
+from wpsite import wp  # noqa: E402
 
 
 def rss_doc(xml: str) -> str:

wpsite/__init__.py

@@ -37,11 +37,10 @@
 
 """
 
-from pathlib import Path
 
+from pathlib import Path
 
 from . import astro
-from . import page
 from . import wp