MINOR: Fix broken link to record format in protocol docs (#5526)
MINOR: Fix broken link to record format in protocol docs (#5526)

Co-authored-by: Mickael Maison <9e7363571ad6c9fdd8a7f0491d2e413bdf6275ab@gmail.com>
Co-authored-by: Gantigmaa Selenge  <6d38b28058c9b62999898d17a1ddc42f1d17508d@gmail.com>

Reviewers: Sriharsha Chintalapani <73a166418032ae2f569b6d7c71df8f05549603d6@apache.org>, Jason Gustafson <jason@confluent.io>
Esquive/kafka,Chasego/kafka,apache/kafka,KevinLiLu/kafka,lindong28/kafka,apache/kafka,KevinLiLu/kafka,gf53520/kafka,lindong28/kafka,gf53520/kafka,guozhangwang/kafka,Chasego/kafka,TiVo/kafka,mihbor/kafka,TiVo/kafka,sslavic/kafka,noslowerdna/kafka,Esquive/kafka,lindong28/kafka,gf53520/kafka,Esquive/kafka,apache/kafka,noslowerdna/kafka,mihbor/kafka,mihbor/kafka,gf53520/kafka,sslavic/kafka,TiVo/kafka,noslowerdna/kafka,Esquive/kafka,guozhangwang/kafka,KevinLiLu/kafka,Chasego/kafka,noslowerdna/kafka,sslavic/kafka,apache/kafka,lindong28/kafka,TiVo/kafka,guozhangwang/kafka,Chasego/kafka,guozhangwang/kafka,KevinLiLu/kafka,mihbor/kafka,sslavic/kafka