Explain default values in the rueidislock README

[rueian]

It might be helpful for other users if you could include the default settings and a brief explanation in the rueidislock README.

Add some explanations to the rueidislock README.

See: #653 (comment)

[nithinputhenveettil]

@rueian : I would like to work on this. Could you please assign this to me? Thanks.

[rueian]

Thanks @nithinputhenveettil!

[rueian]

Hi @nithinputhenveettil, any updates?

[nithinputhenveettil]

@rueian: Sorry, I was caught up with some other work. I’ll share an update with you by this weekend or early next week.