Removing filler words and passive voice from docs

[bradhanks]

          I am strongly in favor of removing filler words and passive voice. I would be ok with removing vague and ambiguous ones too, if they are being harmful, but I wouldn't necessarily chase them.

I would keep the polite language and I only use uncertain words when the uncertainty is desired anyway, so to me they serve a clear purpose. :)

Originally posted by @josevalim in #352 (comment)