feat: add ruff formatter and improve ruff root finding (#66)

* Add ruff formatter and improve ruff root finding

* Add docs

README.md

@@ -203,6 +203,7 @@ To view configured and available formatters, as well as to see the log file, run
 - [prettierd](https://github.com/fsouza/prettierd) - prettier, as a daemon, for ludicrous formatting speed.
 - [rubocop](https://github.com/rubocop/rubocop) - Ruby static code analyzer and formatter, based on the community Ruby style guide.
 - [ruff](https://beta.ruff.rs/docs/) - An extremely fast Python linter, written in Rust.
+- [ruff_format](https://beta.ruff.rs/docs/) - An extremely fast Python linter, written in Rust. Formatter subcommand.
 - [rustfmt](https://github.com/rust-lang/rustfmt) - A tool for formatting rust code according to style guidelines.
 - [rustywind](https://github.com/avencera/rustywind) - A tool for formatting Tailwind CSS classes.
 - [scalafmt](https://github.com/scalameta/scalafmt) - Code formatter for Scala.

doc/conform.txt

@@ -215,6 +215,7 @@ FORMATTERS                                                    *conform-formatter
 `rubocop` - Ruby static code analyzer and formatter, based on the community Ruby
           style guide.
 `ruff` - An extremely fast Python linter, written in Rust.
+`ruff_format` - An extremely fast Python linter, written in Rust. Formatter subcommand.
 `rustfmt` - A tool for formatting rust code according to style guidelines.
 `rustywind` - A tool for formatting Tailwind CSS classes.
 `scalafmt` - Code formatter for Scala.

lua/conform/formatters/ruff.lua

@@ -15,5 +15,6 @@ return {
   stdin = true,
   cwd = require("conform.util").root_file({
     "pyproject.toml",
+    "ruff.conf",
   }),
 }

lua/conform/formatters/ruff_format.lua

@@ -0,0 +1,18 @@
+return {
+  meta = {
+    url = "https://beta.ruff.rs/docs/",
+    description = "An extremely fast Python linter, written in Rust. Formatter subcommand.",
+  },
+  command = "ruff",
+  args = {
+    "format",
+    "--stdin-filename",
+    "$FILENAME",
+    "-",
+  },
+  stdin = true,
+  cwd = require("conform.util").root_file({
+    "pyproject.toml",
+    "ruff.conf",
+  }),
+}