Add support for manual spans, expand instrumentation (#44663)

Release Notes:

- N/A

---------

Co-authored-by: Cameron <cameron@zed.dev>

crates/multi_buffer/src/multi_buffer.rs

@@ -1202,6 +1202,7 @@ impl MultiBuffer {
     }
 
     /// Returns an up-to-date snapshot of the MultiBuffer.
+    #[ztracing::instrument(skip_all)]
     pub fn snapshot(&self, cx: &App) -> MultiBufferSnapshot {
         self.sync(cx);
         self.snapshot.borrow().clone()
@@ -1927,6 +1928,7 @@ impl MultiBuffer {
         cx.notify();
     }
 
+    #[ztracing::instrument(skip_all)]
     pub fn excerpts_for_buffer(
         &self,
         buffer_id: BufferId,
@@ -2887,6 +2889,7 @@ impl MultiBuffer {
         cx.notify();
     }
 
+    #[ztracing::instrument(skip_all)]
     fn sync(&self, cx: &App) {
         let changed = self.buffer_changed_since_sync.replace(false);
         if !changed {
@@ -5627,6 +5630,7 @@ impl MultiBufferSnapshot {
     /// excerpt
     ///
     /// Can optionally pass a range_filter to filter the ranges of brackets to consider
+    #[ztracing::instrument(skip_all)]
     pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
         &self,
         range: Range<T>,