example MAKE_ENV+=FOO=${BAR} is changed to MAKE_ENV+=FOO=${BAR:Q}. Some
other changes are outlined in
http://mail-index.netbsd.org/tech-pkg/2005/12/02/0034.html
for a possessive (like her, his, whose, their, and its).
Note that I didn't check for proper use of "its" (when it should
be "it is" or "it has" instead).
I also saw over 15 other grammar or punctuation problems, but not
fixed in this commit.
