Remove unnecessary Option from functions querying buffer outline (#37935)

`None` case wasn't being used

Release Notes:

- N/A

crates/project/src/task_inventory.rs

@@ -986,7 +986,7 @@ impl ContextProvider for BasicContextProvider {
         let buffer = location.buffer.read(cx);
         let buffer_snapshot = buffer.snapshot();
         let symbols = buffer_snapshot.symbols_containing(location.range.start, None);
-        let symbol = symbols.unwrap_or_default().last().map(|symbol| {
+        let symbol = symbols.last().map(|symbol| {
             let range = symbol
                 .name_ranges
                 .last()