[Checkers] Spaces in commented JSR 308 annotations

[Adam Kiezun]

> If javac ignores spaces when deciding whether to ignore the "/*" and "*/",
> then it issues a warning because "pure" is not defined as an annotation:

good point. I did not think of that.

> If it would help (and especially if it would make you, or Sung, use the
> compiler regularly),

I could live with either of those options.
./adam