Added more highlightings

[En3Tho]

More highlightings for F#!

1. Computation expressions
2. Extension methods
3. Extension properties
   4. Generic constraints (not a separate option, gets auto highlighted like method or property)
   5. F# methods (let functions compiled as methods) (goes to FSharp functions)
4. F# value functions
5. F# mutable value functions
6. Units of measure

Before:

After:

There is still work to do with parameter highlighting, but after spending some time and getting no result I've decided to try pulling this as it already covers about 90% of what I wanted to do

TODO:

• Fix current tests. I need some advice here becase I have to change "gold" files and maybe you don't really need all those new highlighting options (althought I personanly find them all useful)
• Add more tests
• Ask someone from compiler team about highlighting of method parameters (couldn't figure out how to do this one, sadly)

[vasily-kirichenko]

String literals and properties are given almost the same color:

[En3Tho]

Yes, but that's all up to the user. You can pick any color you want. I just wanted to demonstrate the ability to pick a color if you want extension methods/props to be more distinguishable. I mean you can try it yourself and get your own results :)
Edit: extension methods and properties by default inherit highliting colors of usual methods and properties

[auduchinok]

@En3Tho It looks very nice! Please add tests for the things that will now be highlighted differently.

[auduchinok]

Fix current tests. I need some advice here becase I have to change "gold" files and maybe you don't really need all those new highlighting options (althought I personanly find them all useful)

It's OK to just update them with newer ids.

Add more tests (if needed)

Please do. 🙂

[En3Tho]

Sorry for the delay. I've fixed old tests and added new ones. Please tell me if there is more work I need to do on this thing.
Sadly, I couldn't find a way to get this FSharpParameter thing with static constrains to work properly. F# compiler knows that when 'T : (static member Two : 'T) - this is a Property and when 'T : (static member Two : unit -> 'T) - now this is a Method but it's either me or API does not give out this kind of info that easily
So it was really easy to confuse properties and methods. Also it gave false results at object instantiation in case like this:

I guess it's better to just leave those things highlighted as simple values for now.
Also, I will note again that FSharp Method's and FSharp Function's are not the same thing - FSharp Method is something we get from the "outside" (e.g. C#) and FSharp Function comes from F#. F# function can either be method or func but we have decided to not give out this kind of info via highlighting.
Also, should I check for [Extension] Attribute when highlighting extension methods? It's mainly for C# I guess and F# shouldn't really care about it internally. But on the other side it might be useful.

[En3Tho]

Also, without IsValCompiledAsMethodCheck things like these are not being shown as methods for some reason:

vs

I find this a kind of bug at F# comp side because it's a value, it's compiled as method, but for some reason it's not a function type. I'd say unit -> 'T signature instead of just 'T would be a more accurate one as it's actually a method

[auduchinok]

@En3Tho Thanks! It's great to see a lot of new things covered in tests, but some cases seem a bit overcomplicated by seemingly not very related code. Could you try stripping some of it so it's easier to see the highlightings that each test case is about?

[auduchinok]

@En3Tho Thanks for this change!
I'm glad you've found a way to highlight the type functions too (I wasn't sure if it's possible to see it via FCS right now).

[auduchinok]

Sorry, I've messed it up a bit trying to push a small cleanup. The changes got merged without closing the PR automatically, so I'll close it manually.

[En3Tho]

No problem. Thank you for accepting :)