Improve documentation

[marcomarsala]

Many options are undocumented:

• Extra homepage checks. (Very occasionally stops homepage caching)
• Only refresh current page when comments made.

[talgalili]

I wanted to know what does it mean "Only refresh current page when comments made." (what happens if this is checked or un-checked?)

[nekohayo]

I am regularly confused by those two options in particular.

• Maybe the 1st one does some checks to ensure that if it's supposed to be displaying the feed of some dynamic posts, it does show the latest posts? (I'm just guessing).
• The second one is particularly confusing, it doesn't really make sense when you read it, as a user. Is it intended to mean "Refresh the corresponding cache file when a comment is posted on a post/page" ? If so, it should say exactly that, instead of "Only refresh current page when comments made", because the current string makes it seem like enabling the option would make the cache NEVER refresh/expire unless a comment is made on a post/page (which I would find a bit hard to believe, why would someone want that?)...

Could you clarify the meaning of those options @donnchawp? Ideally by rewriting the strings presented in the UI, or at least documenting them in the FAQ.

[nekohayo]

Other uptions that are kind of confusing:

• List the newest cached pages on this page. I've never seen the result of enabling this option. Nothing more is shown on the Advanced tab's page when it is enabled. What is it for?
• Coarse file locking. You do not need this as it will slow down your website. Why is the option there if it says "You do not need this" and "it will slow down your website"?