codemod: seqDef -> SeqDef

SeqDef is a type name, so it should start with a Capital letter.
It's an internal symbol, no impact on public API.

lib/dictBuilder/zdict.c

@@ -608,7 +608,7 @@ static void ZDICT_countEStats(EStats_ress_t esr, const ZSTD_parameters* params,
             }
 
             if (nbSeq >= 2) { /* rep offsets */
-                const seqDef* const seq = seqStorePtr->sequencesStart;
+                const SeqDef* const seq = seqStorePtr->sequencesStart;
                 U32 offset1 = seq[0].offBase - ZSTD_REP_NUM;
                 U32 offset2 = seq[1].offBase - ZSTD_REP_NUM;
                 if (offset1 >= MAXREPOFFSET) offset1 = 0;