Cleanup wording of dictScan() comment
Cleanup wording of dictScan() comment

Some language in the comment was difficult
to understand, so this commit: clarifies wording, removes
unnecessary words, and relocates some dependent clauses
closer to what they actually describe.

I also tried to break up longer chains of thought
(if X, then Y, and Q, and also F, so obviously M)
into more manageable chunks for ease of understanding.

janeasystems/redis,enginekit/redis,adamweixuan/redis,quangnguyen90/redis,shanegxxiao/redis,enginekit/redis,ideaar/redis,damy/redis,jaambee/redis,kolonse/redis,quangnguyen90/redis,Cybermaxs/redis,kts12345/redis,erwin00776/redis-2.8-optimize,enginekit/redis,sidsen/redis,jacklee0810/redis,kts12345/redis,shanegxxiao/redis,quangnguyen90/redis,alpha8/redis,miminus/redis,adamweixuan/redis,adamweixuan/redis,miminus/redis,kts12345/redis,alpha8/redis,Cybermaxs/redis,laurencee/redis,hanmichael/redis,adamweixuan/redis,laurencee/redis,janeasystems/redis,jaambee/redis,ScottKaiGu/redis,Cybermaxs/redis,Jonavin/redis,quangnguyen90/redis,jqk6/redis,upsoft/redis,Cybermaxs/redis,ideaar/redis,liqiang199105/redis,damy/redis,quangnguyen90/redis,upsoft/redis,hanmichael/redis,kolonse/redis,alpha8/redis,alpha8/redis,jacklee0810/redis,liqiang199105/redis,sidsen/redis,damy/redis,erwin00776/redis-2.8-optimize,jacklee0810/redis,kolonse/redis,damy/redis,damy/redis,jqk6/redis,miminus/redis,alpha8/redis,LittlePeng/redis,ScottKaiGu/redis,erwin00776/redis-2.8-optimize,jaambee/redis,upsoft/redis,sidsen/redis,kolonse/redis,ideaar/redis,kts12345/redis,ScottKaiGu/redis,jacklee0810/redis,ScottKaiGu/redis,laurencee/redis,liqiang199105/redis,Jonavin/redis,janeasystems/redis,shanegxxiao/redis,sidsen/redis,LittlePeng/redis,kolonse/redis,laurencee/redis,hanmichael/redis,LittlePeng/redis,janeasystems/redis,jqk6/redis,hanmichael/redis,kts12345/redis,liqiang199105/redis,miminus/redis,laurencee/redis,sidsen/redis,jaambee/redis,ScottKaiGu/redis,Jonavin/redis,shanegxxiao/redis,upsoft/redis,jqk6/redis,liqiang199105/redis,Cybermaxs/redis,enginekit/redis,Jonavin/redis,adamweixuan/redis,miminus/redis,jacklee0810/redis,hanmichael/redis,janeasystems/redis,shanegxxiao/redis,erwin00776/redis-2.8-optimize,jqk6/redis,Jonavin/redis,ideaar/redis,sidsen/redis,enginekit/redis,upsoft/redis,ideaar/redis,jaambee/redis