Allow for function JSDoc on let and const nodes.

Fixes #749 on Github.
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=82717970
In a statement like "var a = b = class {}", count the "b" node as the class name.

Fixes #752 on Github.
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=82746074
Get rid of unnecessary []'s in function type annotations. Annotations such as

@type {function(...[Foo])}

are rewritten as

@type {function(...Foo)}

The []'s are no longer necessary as of the r20141103 compiler release, and getting rid of them entirely will allow us to add support for "tuples" (heterogeneous fixed-length arrays) in the future.
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=82746936