Fix typo in 6.24.0 HISTORY.md (#8694)

Summary:
fix typo

Also, clarified change of C API signatures.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8694

Test Plan: visual

Reviewed By: ltamasi

Differential Revision: D30492882

Pulled By: pdillinger

fbshipit-source-id: ac6dc3dcefa01c91fd87fc7f50279ea5e13fa41d

HISTORY.md

@@ -25,10 +25,10 @@
 * The integrated BlobDB implementation now supports the tickers `BLOB_DB_BLOB_FILE_BYTES_READ`, `BLOB_DB_GC_NUM_KEYS_RELOCATED`, and `BLOB_DB_GC_BYTES_RELOCATED`, as well as the histograms `BLOB_DB_COMPRESSION_MICROS` and `BLOB_DB_DECOMPRESSION_MICROS`.
 * Added hybrid configuration of Ribbon filter and Bloom filter where some LSM levels use Ribbon for memory space efficiency and some use Bloom for speed. See NewRibbonFilterPolicy. This also changes the default behavior of NewRibbonFilterPolicy to use Bloom for flushes under Leveled and Universal compaction and Ribbon otherwise. The C API function `rocksdb_filterpolicy_create_ribbon` is unchanged but adds new `rocksdb_filterpolicy_create_ribbon_hybrid`.
 
-## Public API change
+### Public API change
 * Added APIs to decode and replay trace file via Replayer class. Added `DB::NewDefaultReplayer()` to create a default Replayer instance. Added `TraceReader::Reset()` to restart reading a trace file. Created trace_record.h, trace_record_result.h and utilities/replayer.h files to access the decoded Trace records, replay them, and query the actual operation results.
 * Added Configurable::GetOptionsMap to the public API for use in creating new Customizable classes.
-* Generalized bits_per_key parameters in C API from int to double for greater configurability.
+* Generalized bits_per_key parameters in C API from int to double for greater configurability. Although this is a compatible change for existing C source code, anything depending on C API signatures, such as foreign function interfaces, will need to be updated.
 
 ### Performance Improvements
 * Try to avoid updating DBOptions if `SetDBOptions()` does not change any option value.