Combining ruff setup from PR #215

To keep the following PR cleaner, this commit moves and combines a few
ruff setup from that PR into here.

style: Adding 'F' into ruff's checks

  It seems to be the only one conforming.

cfg: Missing to ignore F401

  Following @bnb32 setup.

style: Ignore F401 only on __init__

  Thanks to @ppinchuk 's tip! I missed that before.

Ignoring unused import in docs

Including Warning (W) rules

pyproject.toml

@@ -77,7 +77,10 @@ fixable = ["ALL"]
 preview = true
 select = [
  "E", # pycodestyle
+ "F", # Pyflakes
+ "W", # Warning
  ]
+
 ignore = [
  "B008", # function-call-in-default-argument
  "B024", # abstract-base-class-without-abstract-method
@@ -100,6 +103,14 @@ ignore = [
  "UP038" # non-pep604-isinstance
  ]
 
+[tool.ruff.lint.per-file-ignores]
+"__init__.py" = [
+ "F401", # unused-import
+ ]
+"docs/source/conf.py" = [
+ "E402", # unused-import
+ ]
+
 [tool.ruff.format]
 quote-style = "single"
 indent-style = "space"