Mention PR 9100 in HISTORY.md (#9111)

Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/9111

Reviewed By: riversand963

Differential Revision: D32076310

Pulled By: ltamasi

fbshipit-source-id: 81e30a02ded87c0f1a42985db42e80b62235ba11

HISTORY.md

@@ -2,6 +2,7 @@
 ## Unreleased
 ### New Features
 * Added new ChecksumType kXXH3 which is faster than kCRC32c on almost all x86\_64 hardware.
+* Added a new online consistency check for BlobDB which validates that the number/total size of garbage blobs does not exceed the number/total size of all blobs in any given blob file.
 
 ### Bug Fixes
 * Prevent a `CompactRange()` with `CompactRangeOptions::change_level == true` from possibly causing corruption to the LSM state (overlapping files within a level) when run in parallel with another manual compaction. Note that setting `force_consistency_checks == true` (the default) would cause the DB to enter read-only mode in this scenario and return `Status::Corruption`, rather than committing any corruption.