doc: add some example to http api doc (#8785)
doc: add some example to http api doc (#8785)


XuHuaiyu/tidb,kyle-wang/tidb,XuHuaiyu/tidb,pingcap/tidb,kyle-wang/tidb,cosmtrek/tidb,coocood/tidb,cosmtrek/tidb,ming-relax/tidb,qiuyesuifeng/tidb,ngaut/tidb,ngaut/tidb,c4pt0r/tidb,ngaut/tidb,EvilMcJerkface/tidb,c4pt0r/tidb,pingcap/tidb,qiuyesuifeng/tidb,kyle-wang/tidb,kyle-wang/tidb,Cofyc/tidb,coocood/tidb,ngaut/tidb,c4pt0r/tidb,ngaut/tidb,kyle-wang/tidb,c4pt0r/tidb,Cofyc/tidb,c4pt0r/tidb,ming-relax/tidb,c4pt0r/tidb,pingcap/tidb,kyle-wang/tidb,EvilMcJerkface/tidb,pingcap/tidb,pingcap/tidb,ngaut/tidb,pingcap/tidb