README: drop S3-FIFOd, list S4-FIFO

S4-FIFO is implemented on dev/s4fifo behind -DENABLE_S4FIFO=ON, so it is
listed the same way as the other flag-gated algorithms (3LCache, GLCache,
LRB). S3-FIFOd comes off the list.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01JxxSd3ipti1DZc58v543JW

Author: claude

README.md

@@ -64,7 +64,8 @@ The name in `code` is what you pass to `cachesim` on the command line (names are
 * [3LCache](/libCacheSim/cache/eviction/3LCache/) `3lcache` — build with `-DENABLE_3L_CACHE=ON`
 * [WTinyLFU](/libCacheSim/cache/eviction/WTinyLFU.c) `wtinylfu`
 * [QD-LP](/libCacheSim/cache/eviction/QDLP.c) `qdlp`
-* [S3-FIFO](/libCacheSim/cache/eviction/S3FIFO.c) `s3fifo`, [S3-FIFOd](/libCacheSim/cache/eviction/S3FIFOd.c) `s3fifod`
+* [S3-FIFO](/libCacheSim/cache/eviction/S3FIFO.c) `s3fifo`
+* [S4-FIFO](/libCacheSim/cache/eviction/S4FIFO/S4FIFO.c) `s4fifo` — build with `-DENABLE_S4FIFO=ON`
 * [Sieve](/libCacheSim/cache/eviction/Sieve.c) `sieve`
 
 ### Admission algorithms