Allow more kinds of @suppress on non-function nodes.

[Dominator008]

Most of the lint warnings from Closure Library are "@Suppress is not allowed here", and many of the use cases seem reasonable to me. Eg.:

/** @suppress {unusedLocalVariables} */
var dummy = 3;

We also need to document where @Suppress is actually allowed, pending TODO by @MatrixFrog in https://github.com/google/closure-compiler/blob/master/src/com/google/javascript/jscomp/lint/CheckJSDocStyle.java#L45-L48.

[dimvar]

I wrote a quick wiki page to say where @suppress is currently supported. https://github.com/google/closure-compiler/wiki/@suppress-annotations

[MatrixFrog]

I'd like to keep the rules for where @suppress is allowed simple enough that people can keep them in their head. I don't want to get into a state where you have to remember that some suppresses are valid in a bunch of places where others are only on functions, and you get mixed up about which is which, all the time. But stretching the rules beyond where they currently are, a little bit, is fine.

[Dominator008]

@MatrixFrog There are currently 187 lint warnings from Closure Library, and 121 of them are "@suppress annotation not allowed here". Most of those @suppress's that I saw were pretty reasonable, which makes me wonder if CheckJSDocStyle is being too strict...

[MatrixFrog]

They are probably in places where gjslint understood them but our linter does not. Getting our linter to understand most/all of the gjslint places is a reasonable request.