docs(asm): state the seed layout of the arch fuzz targets exactly

Assisted-by: GLM 5.3

asm/assembler_fuzz_test.go

@@ -202,8 +202,9 @@ func FuzzAssembleARM64(f *testing.F) {
 // the I-type arithmetic, the load/store and branch offsets, the atomics, the
 // FP conversions and the fused multiply-adds), the RVV configuration and
 // arithmetic classes with their mask forms, the RVC-compressible shapes, the
-// CSR instructions and the Zbb/Zba/Zbs bit-manipulation set, plus one file per
-// rejection shape so each diagnostic path replays on its own.
+// CSR instructions and the Zbb/Zba/Zbs bit-manipulation set, minimalised.
+// The inline seeds below pin the shared file-level surface and the rejection
+// shapes, one diagnostic path each.
 func FuzzAssembleRISCV64(f *testing.F) {
 	corpusSeeds(f)
 	archCorpusSeeds(f, "riscv64")
@@ -244,7 +245,9 @@ func FuzzAssembleRISCV64(f *testing.F) {
 // biased shifts, the VSHUF4I/VPERMI/VEXTRINS immediates), the ll/sc offset
 // ladder with its three encoding spans, the pointer loads and stores, the
 // atomics with their dbar forms, the branches, the bit-field instructions and
-// the register-class moves, plus one file per rejection shape.
+// the register-class moves, minimalised.  The inline seeds below pin the
+// shared file-level surface and the rejection shapes, one diagnostic path
+// each.
 func FuzzAssembleLOONG64(f *testing.F) {
 	corpusSeeds(f)
 	archCorpusSeeds(f, "loong64")