CXX-3093 Add changelog entry for ABI symbol removal

Author: eramongodb

CHANGELOG.md

@@ -22,6 +22,18 @@ Changes prior to 3.9.0 are documented as [release notes on GitHub](https://githu
 - A future minor release plans to raise the minimum supported MongoDB Server version from 3.6 to 4.0. This is in
 accordance with [MongoDB Software Lifecycle Schedules](https://www.mongodb.com/legal/support-policy/lifecycles).
 
+### Removed
+
+- Export of private member functions in bsoncxx:
+  - `bsoncxx::v_noabi::types::bson_value::value::value(const uint8_t*, uint32_t, uint32_t, uint32_t)`
+  - `bsoncxx::v_noabi::types::bson_value::view::_init(void*)`
+  - `bsoncxx::v_noabi::types::bson_value::view::view(const uint8_t*, uint32_t, uint32_t, uint32_t)`
+  - `bsoncxx::v_noabi::types::bson_value::view::view(void*)`
+- Export of private member functions in mongocxx:
+  - `mongocxx::v_noabi::options::change_stream::as_bson()`
+  - `mongocxx::v_noabi::options::aggregate::append(bsoncxx::v_noabi::builder::basic::document&)`
+  - `mongocxx::v_noabi::options::index::storage_options()`
+
 ## 3.10.3 [Unreleased]
 
 <!-- Will contain entries for the next patch release -->