ML-KEM: fix comments, API signatures, minor issues #2488

Job	Run time
make check (--enable-all --enable-sm2 --enable-sm3 --enable-sm4-ecb --enable-sm4-cbc --enable-sm4...	3m 8s
make check (--enable-sm2 --enable-sm3 --enable-sm4-ecb --enable-sm4-cbc --enable-sm4-ctr --enable...	1m 2s
make check (--enable-sm2 --enable-sm3 --enable-sm4-gcm --enable-sm4-ccm --enable-sha3)	59s
	5m 9s

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