Remove jupyter_notebook features

## Summary

Remove the `jupyter_notebook` feature. This is now handled by the `include` feature introduced in #3914

## Test Plan

I have confirmed that running `cargo run --bin ruff -- check --select F841 --no-cache dir_with_notebook/` doesn't pick them up, but adding `include = ["*.ipynb"]` in `pyproject.toml` makes the notebooks found.

crates/ruff/src/jupyter/notebook.rs

@@ -43,9 +43,6 @@ pub fn round_trip(path: &Path) -> anyhow::Result<String> {
 pub fn is_jupyter_notebook(path: &Path) -> bool {
     path.extension()
         .map_or(false, |ext| ext == JUPYTER_NOTEBOOK_EXT)
-        // For now this is feature gated here, the long term solution depends on
-        // https://github.com/astral-sh/ruff/issues/3410
-        && cfg!(feature = "jupyter_notebook")
 }
 
 impl Cell {
@@ -410,7 +407,6 @@ mod test {
     use test_case::test_case;
 
     use crate::jupyter::index::JupyterIndex;
-    #[cfg(feature = "jupyter_notebook")]
     use crate::jupyter::is_jupyter_notebook;
     use crate::jupyter::schema::Cell;
     use crate::jupyter::Notebook;
@@ -473,7 +469,6 @@ mod test {
     }
 
     #[test]
-    #[cfg(feature = "jupyter_notebook")]
     fn inclusions() {
         let path = Path::new("foo/bar/baz");
         assert!(!is_jupyter_notebook(path));

crates/ruff_cli/Cargo.toml

@@ -66,9 +66,6 @@ wild = { version = "2" }
 assert_cmd = { version = "2.0.8" }
 ureq = { version = "2.6.2", features = [] }
 
-[features]
-jupyter_notebook = ["ruff/jupyter_notebook"]
-
 [target.'cfg(target_os = "windows")'.dependencies]
 mimalloc = "0.1.34"
 

crates/ruff_cli/src/commands/run.rs

@@ -188,7 +188,6 @@ with the relevant file contents, the `pyproject.toml` settings, and the followin
 }
 
 #[cfg(test)]
-#[cfg(feature = "jupyter_notebook")]
 mod test {
     use std::path::PathBuf;
     use std::str::FromStr;