Document @noinline

[realityforge]

I was just directed to an issue that indicates @noinline is supported by the compiler but it is not documented on the wiki. It would be great if a short description was that indicated any of the non-obvious implications ... if there are any :)

[blickly]

Internal issue created http://b/129431114

[lauraharker]

I added https://github.com/google/closure-compiler/wiki/Annotating-JavaScript-for-the-Closure-Compiler#noinline.

The only non-obvious implication is that there may be code paths in the compiler that do not honor this annotation, although it works in the common case. (See Bradford's comment here #2751 (comment))