Rewrite to remove inaccurate @ logging text.

I did some basic tests, and it looks like the linked SitePoint article is incorrect about the error control operator logging errors. An `@` will completely swallow an expression's error. The point about "harmless" notices/warnings potentially filling up the log is valid, but belongs in the error reporting section and not in the error control operator section. 

I've rewritten the section to remove reference to the logging, and explain the tradeoffs involved in the lack of error logging from `@`. Also, some passive voice rewrites.