Replace ruff-lsp links in README.md with links to new documentation page (#12618)

Since `ruff-lsp` has been (semi-)deprecated for sometime, it wouldn't
make sense to mention it in the most prominent sections of the `README`.
Instead, they should point to the new <i>[Editor
Integrations](https://docs.astral.sh/ruff/editors/)</i> documentation
page.

scripts/generate_mkdocs.py

@@ -62,6 +62,7 @@ LINK_REWRITES: dict[str, str] = {
         "configuration.md#pyprojecttoml-discovery"
     ),
     "https://docs.astral.sh/ruff/contributing/": "contributing.md",
+    "https://docs.astral.sh/ruff/editors/setup": "editors/setup.md",
     "https://docs.astral.sh/ruff/integrations/": "integrations.md",
     "https://docs.astral.sh/ruff/faq/#how-does-ruff-compare-to-flake8": (
         "faq.md#how-does-ruff-compare-to-flake8"