Colorize ruff output when run through tox

In most other situations it is typically already colorized.

This also includes comments about how to override this to suppress
color.

Author: EliahKagan

tox.ini

@@ -13,12 +13,16 @@ commands = pytest --color=yes {posargs}
 description = Lint with Ruff
 base_python = py{39,310,311,312,38,37}
 deps = ruff
+set_env =
+    CLICOLOR_FORCE = 1  # Set NO_COLOR to override this.
 commands = ruff check .
 
 [testenv:format]
 description = Check formatting with Ruff
 base_python = py{39,310,311,312,38,37}
 deps = ruff
+set_env =
+    CLICOLOR_FORCE = 1  # Set NO_COLOR to override this.
 commands = ruff format --check .
 
 [testenv:mypy]