Make Buffer::apply_ops infallible (#18089)

This PR makes the `Buffer::apply_ops` method infallible for
`text::Buffer` and `language::Buffer`.

We discovered that `text::Buffer::apply_ops` was only fallible due to
`apply_undo`, which didn't actually need to be fallible.

Release Notes:

- N/A

crates/collab/src/db/queries/buffers.rs

@@ -689,9 +689,7 @@ impl Database {
         }
 
         let mut text_buffer = text::Buffer::new(0, text::BufferId::new(1).unwrap(), base_text);
-        text_buffer
-            .apply_ops(operations.into_iter().filter_map(operation_from_wire))
-            .unwrap();
+        text_buffer.apply_ops(operations.into_iter().filter_map(operation_from_wire));
 
         let base_text = text_buffer.text();
         let epoch = buffer.epoch + 1;

crates/collab/src/db/tests/buffer_tests.rs

@@ -96,16 +96,14 @@ async fn test_channel_buffers(db: &Arc<Database>) {
         text::BufferId::new(1).unwrap(),
         buffer_response_b.base_text,
     );
-    buffer_b
-        .apply_ops(buffer_response_b.operations.into_iter().map(|operation| {
-            let operation = proto::deserialize_operation(operation).unwrap();
-            if let language::Operation::Buffer(operation) = operation {
-                operation
-            } else {
-                unreachable!()
-            }
-        }))
-        .unwrap();
+    buffer_b.apply_ops(buffer_response_b.operations.into_iter().map(|operation| {
+        let operation = proto::deserialize_operation(operation).unwrap();
+        if let language::Operation::Buffer(operation) = operation {
+            operation
+        } else {
+            unreachable!()
+        }
+    }));
 
     assert_eq!(buffer_b.text(), "hello, cruel world");