Fixes https://github.com/fdorg/flashdevelop/issues/444 - #510

Actually ASFileParser is parsing the declarations correctly (it only misses the escaped quotes in the string value).
The problem is in ASComplete when showing the method call tip: the highlight stops at the first coma, but that's only a visual artifact.

Our implementation of FindNearSymbolInFunctDefis quite bad (a badly reviewed code contribution) but your PR doesn't push it in the right direction.

The escaped quotes were what I was referring to when I said it doesn't play nice with that :)
The code isn't nice from a conceptual level to begin with: There's an ASFileParser that does the parsing, why reimplement parsing in ASComplete where we should probably only consume parsed information? I just went with what was there to try and make a non-intrusive fix for that, instead of trying to mess with the underlying issue (for which I'd need a more complete overview of the codebase), naturally resulting in a poor fix for an embarassing bug :)

Let's say that it's complicated - this has grown organically, based on the initial choice that using a proper parser with AST and all was a complexity we couldn't afford (it really has considerable consequences). So ASFileParser only builds superficial models and ASComplete has to do some local parsing. That kind of crappy I admit.

Now the real problem here is the method's hint highlighting: it is applied on the text of the hint (which requires parsing) instead of the hint text+highlighting tags being constructed from the method's model that we have also at this point in the code.