Use OneIndexed in NotebookIndex (#7921)

## Summary

This PR refactors the `NotebookIndex` struct to use `OneIndexed` to make
the
intent of the code clearer.

## Test Plan

Update the existing test case and run `cargo test` to verify the change.

- [x] Verify `--diff` output
- [x] Verify the diagnostics output
- [x] Verify `--show-source` output

crates/ruff_notebook/src/index.rs

@@ -1,5 +1,7 @@
 use serde::{Deserialize, Serialize};
 
+use ruff_source_file::OneIndexed;
+
 /// Jupyter Notebook indexing table
 ///
 /// When we lint a jupyter notebook, we have to translate the row/column based on
@@ -7,20 +9,20 @@ use serde::{Deserialize, Serialize};
 #[derive(Clone, Debug, Eq, PartialEq, Serialize, Deserialize)]
 pub struct NotebookIndex {
     /// Enter a row (1-based), get back the cell (1-based)
-    pub(super) row_to_cell: Vec<u32>,
+    pub(super) row_to_cell: Vec<OneIndexed>,
     /// Enter a row (1-based), get back the row in cell (1-based)
-    pub(super) row_to_row_in_cell: Vec<u32>,
+    pub(super) row_to_row_in_cell: Vec<OneIndexed>,
 }
 
 impl NotebookIndex {
     /// Returns the cell number (1-based) for the given row (1-based).
-    pub fn cell(&self, row: usize) -> Option<u32> {
-        self.row_to_cell.get(row).copied()
+    pub fn cell(&self, row: OneIndexed) -> Option<OneIndexed> {
+        self.row_to_cell.get(row.to_zero_indexed()).copied()
     }
 
     /// Returns the row number (1-based) in the cell (1-based) for the
     /// given row (1-based).
-    pub fn cell_row(&self, row: usize) -> Option<u32> {
-        self.row_to_row_in_cell.get(row).copied()
+    pub fn cell_row(&self, row: OneIndexed) -> Option<OneIndexed> {
+        self.row_to_row_in_cell.get(row.to_zero_indexed()).copied()
     }
 }