bug#3661: English errors in help for whitespace-style

There are some English errors in the help for the whitespace-style
variable that render some of the text virtually unintelligible to a
native English speaker (or at least to this particular native English
speaker).

Original:

   space-after-tab::space	TABs are visualized when occurs 8 or
				more SPACEs after a TAB via faces.

I would say

   space-after-tab::space	TABs are visualized using faces when 8 or
				more SPACEs occur after a TAB.

Original:

   space-before-tab::space	TABs are visualized when occurs SPACEs
				before TAB via faces.

I would say:

   space-before-tab::space	TABs are visualized using faces when
				SPACEs occur before TAB.

At least I think that's what I would say based on what I think the
variable seems to do, though I can't really tell from the original
wording.  (This is not a criticism of the author, whose English is much
better than my abilities in any non-English language!)

I would be willing to go through the documentation strings to help clean
up the English if it would help.

-- 
Jay Berkenbilt <[email protected]>