kv/typo: fix the description for `GetMemCache` (#22766)
kv/typo: fix the description for `GetMemCache` (#22766)

Signed-off-by: mwish <204447172a40e7539c36ea62a1bddf0914069ccf@qq.com>
ngaut/tidb,pingcap/tidb,kyle-wang/tidb,ngaut/tidb,kyle-wang/tidb,c4pt0r/tidb,pingcap/tidb,coocood/tidb,c4pt0r/tidb,kyle-wang/tidb,ngaut/tidb,pingcap/tidb,coocood/tidb,ngaut/tidb,c4pt0r/tidb,pingcap/tidb,c4pt0r/tidb,kyle-wang/tidb,pingcap/tidb,c4pt0r/tidb,kyle-wang/tidb,ngaut/tidb,c4pt0r/tidb,ngaut/tidb,pingcap/tidb,kyle-wang/tidb