Enable clippy::redundant_locals (#8750)

This PR enables the
[`clippy::redundant_locals`](https://rust-lang.github.io/rust-clippy/master/index.html#/redundant_locals)
rule and fixes the outstanding violations.

Release Notes:

- N/A

crates/semantic_index/src/semantic_index.rs

@@ -840,7 +840,6 @@ impl SemanticIndex {
             let mut batch_results = Vec::new();
             for batch in file_ids.chunks(batch_size) {
                 let batch = batch.into_iter().map(|v| *v).collect::<Vec<i64>>();
-                let limit = limit;
                 let fs = fs.clone();
                 let db_path = db_path.clone();
                 let query = query.clone();